Light-emitting dies incorporating wavelength-conversion materials and related methods

ABSTRACT

In accordance with certain embodiments, electronic devices feature a polymeric binder, a frame defining an aperture therethrough, and a semiconductor die (e.g., a light-emitting or a light-detecting element) suspended in the binder and within the aperture of the frame.

RELATED APPLICATIONS

This application claims the benefit of and priority to U.S. ProvisionalPatent Application No. 61/936,050, filed Feb. 5, 2014, and U.S.Provisional Patent Application No. 61/971,748, filed Mar. 28, 2014, theentire disclosure of each of which is hereby incorporated herein byreference.

FIELD OF THE INVENTION

In various embodiments, the present invention generally relates to lightsources, and more specifically to phosphor-converted light sources.

BACKGROUND

Light sources such as light-emitting diodes (LEDs) are an attractivealternative to incandescent and fluorescent light bulbs in illuminationdevices due to their higher efficiency, smaller form factor, longerlifetime, and enhanced mechanical robustness. However, the high cost ofLED-based lighting systems has limited their widespread utilization,particularly in broad-area general lighting applications.

The high cost of LED-based lighting systems has several contributors.LED chips are typically encased in a package, and multiple packaged LEDsare used in each lighting system to achieve the desired light intensity.For general illumination, which utilizes white light, such white lightmay be generated in a number of ways. One approach is to utilize two ormore LEDs operating at different wavelengths, where the differentwavelengths combine to appear white to the human eye. For example, LEDsemitting in the red, green and blue wavelength ranges may be utilizedtogether. Such an arrangement typically requires careful control of theoperating currents of each LED, such that the resulting combination ofwavelengths is stable over time and different operating conditions, forexample temperature. The different LEDs may also be formed fromdifferent materials, for example, AlInGaP for red LEDs and AlInGaN forblue and green LEDs. These different materials may have differentoperating current requirements as well as different temperaturedependencies of the light output power and wavelength. Furthermore,changes in light-output power with time may be different for each typeof LED. Therefore, such systems typically utilize some form of activecontrol of the current in each LED to maintain the light output power ofeach LED at the desired level. In some implementations, one or moresensors (for example to sense light intensity, light color, temperatureor the like) may be used to provide feedback to the current-controlsystem, while in some other implementations the current may be adjustedover time based on values in a look-up table. Such control systems addcost and complexity to lighting solutions, as well as creatingadditional potential failure points. A further disadvantage of multi-LEDarrangements is that they typically require some form of light combiner,diffuser or mixing chamber, so that the eye observes white light ratherthan the discrete different colors of each of the different LEDs. Suchlight-mixing systems typically add cost and bulk to lighting systems andmay reduce their efficiency.

White light may also be produced in LED-based systems for generalillumination by means of light-conversion materials such as phosphors.LEDs generally emit in a relatively narrow wavelength range, for exampleon the order of about 20-100 nm. When broader spectra (for example“white” light) or colors different from that of the LED are desired, theLED may be combined with one or more light-conversion materials. An LEDcombined with one or more phosphors typically generates white light bycombining the short-wavelength emission from the semiconductor LED withlong-wavelength emission from the phosphor(s). This occurs because aportion of the LED light passes unconverted through the phosphor tocombine with the phosphor-converted light. Phosphors are typicallycomposed of phosphorescent particles such as Y₃Al₅O₁₂:Ce³⁺(cerium-activated yttrium-aluminum-garnet, or YAG:Ce) embedded in atransparent binder such as optical epoxy or silicone and applied as alayer. However, phosphor integration is often difficult, particularly interms of uniformity and reproducibility of the resulting light.

In some phosphor implementations, the phosphor layer absorbs a portionof the incident short-wavelength radiant flux and re-emitslong-wavelength radiant flux. In an exemplary YAG:Ce phosphor, a blueLED typically has a peak wavelength of 450 nm-460 nm, corresponding tothe peak of the phosphor-excitation spectrum, while the phosphoremission has a broadband spectrum with a peak at approximately 560 nm.Combining the blue LED emission with the yellow phosphor emission yieldsvisible white light with a specific chromaticity (color) that depends onthe ratio of blue to yellow light.

The geometry of the phosphor relative to the LED generally has a verystrong impact on the uniformity of the light characteristics. Forexample, the LED may emit from more than one surface, for example fromthe top and the sides of the LED, producing non-uniform color if thephosphor composition is not uniform over these LED surfaces. Morecomplicated structures may be used to attempt to mitigate this problem,but these add cost and complexity and may be additional sources forreliability problems.

Furthermore, if the thickness of the phosphor layer, formed of auniformly dispersed phosphor in a binder, is not uniform over thesurface of the LED, relatively larger amounts of blue light will bepresent where the phosphor-infused binder layer is thinner andrelatively smaller amounts of blue light will be present where thephosphor-infused binder is thicker. In view of the foregoing, a needexists for structures, systems and procedures enabling the uniform andlow-cost integration of phosphors with illumination devices such asLEDs.

SUMMARY

In accordance with certain embodiments, semiconductor dies such aslight-emitting elements (LEEs) are positioned within a frame and coatedwith a binder, which is subsequently cured to form a composite framewafer that includes or consists essentially of the frame, the solidbinder material, and the dies suspended therein. The composite framewafer may be divided into free-standing “frame dies” each composed ofthe die and a portion of the cured binder that at least partiallysurrounds the die and a portion of the frame that at least partiallysurrounds the binder. The binder may advantageously contain awavelength-conversion material such as a phosphor or a collection ofquantum dots. Various mold substrates and/or molds may be utilized tosecure the semiconductor dies and/or to prevent coating of the contactsof the dies during the coating process.

In an aspect, embodiments of the invention feature a method of forming acomposite frame wafer comprising or consisting essentially of (i) aframe wafer defining a plurality of apertures therethrough and (ii) aplurality of discrete semiconductor dies suspended in a cured polymericbinder within the apertures. A frame wafer is provided. The frame wafer(i) has a bottom surface, (ii) has a top surface opposite the bottomsurface, (iii) has a thickness spanning the top and bottom surfaces, and(iv) defines a plurality of apertures fully through the thickness. Thetop surface of the frame wafer surrounds each aperture. The aperturesmay each have a sidewall not perpendicular to the bottom surface of theframe wafer. The frame wafer is disposed over or on a mold substrate.The plurality of discrete semiconductor dies are disposed over or on themold substrate within the apertures. Each semiconductor die has at leasttwo spaced-apart contacts adjacent the mold substrate. At least aportion of the frame wafer and the plurality of semiconductor dies arecoated with a polymeric binder. The polymeric binder is cured to formthe composite frame wafer. The contacts of each semiconductor die remainat least partially uncoated by the polymeric binder.

Embodiments of the invention may include one or more of the following inany of a variety of combinations. One or more of the semiconductor diesmay be a bare-die light-emitting element. The polymeric binder may betransparent to a wavelength of light emitted by the one or moresemiconductor dies. The frame wafer may be transparent to a wavelengthof light emitted by a light-emitting element. A reflective layer may beformed on at least a portion of the frame wafer. At least a portion ofthe sidewall of at least one of the apertures (i.e., all or a portion ofthe sidewall material itself and/or a reflective coating disposedthereon) may be reflective to a wavelength of light emitted by thelight-emitting element. A reflectance of the at least a portion of thesidewall may vary with incident angle (of light incident upon the atleast a portion of the sidewall) and/or incident wavelength (of lightincident upon the at least a portion of the sidewall). The at least aportion of the sidewall may have a reflectance greater than 80%, or evengreater than 90%, to a wavelength of light emitted by the light-emittingelement. The at least a portion of the sidewall may be a substantiallydiffuse reflector or a substantially specular reflector. The at least aportion of the sidewall may be coated with a reflective coating that isreflective to a wavelength of light emitted by the light-emittingelement. The reflective coating may include, consist essentially of, orconsist of aluminum, silver, gold, silicon dioxide, titanium dioxide,and/or silicon nitride. The reflective coating may include, consistessentially of, or consist of (i) a reflecting film and/or (ii) aplurality of particles.

The polymeric binder may contain a wavelength-conversion material forabsorption of at least a portion of light emitted from the semiconductordies and emission of converted light having a different wavelength, andconverted light and unconverted light emitted by the semiconductor diesmay combine to form mixed light. The wavelength-conversion material mayinclude, consist essentially of, or consist of a phosphor and/or quantumdots. At least a portion of the sidewall of at least one of theapertures may be coated with reflective coating having a reflectancegreater than 80%, or even greater than 90%, to a wavelength of lightemitted by the light-emitting element and/or the wavelength-conversionmaterial. The polymeric binder may include, consist essentially of, orconsist of a plurality of discrete regions, at least one of whichincludes, consists essentially of, or consists of the polymeric binderwithout the wavelength-conversion material. The mixed light may include,consist essentially of, or consist of substantially white light. Thesubstantially white light may have a correlated color temperature in therange of 2000 K to 10,000 K. The variation in the color temperature ofthe substantially white light emitted when each semiconductor die isindividually energized may be less than four MacAdam ellipses, or evenless than two MacAdam ellipses, across the composite frame wafer. Thevariation in the color temperature of the substantially white lightemitted when each semiconductor die is individually energized may beless than 500 K, or even less than 250 K, across the composite framewafer. The maximum divergence of color uniformity in terms of theradially averaged Δu′v′ deviation from the spatially weighted averagewhen each semiconductor die is individually energized may be less than0.01, or even less than 0.006, across the composite frame wafer. Thedivergence of color temperature of the substantially white light emittedwhen each semiconductor die is individually energized, may vary, over anangular range of 0° to 80°, no more than 0.006 in terms of Δu′v′deviation from a spatially weighted averaged chromaticity across thecomposite frame wafer. The divergence of color temperature of thesubstantially white light emitted when each semiconductor die isindividually energized, may vary, over an angular range of 10° to 75°,no more than 0.005 in terms of Δu′v′ deviation from a spatially weightedaveraged chromaticity across the composite frame wafer.

The composite frame wafer may be separated into a plurality of discreteportions. Each portion may include, consist essentially of, or consistof (i) a portion of the frame wafer defining an aperture therethroughand (ii) disposed within the aperture, at least one semiconductor diecoated with cured polymeric binder. After separation, the volume ofpolymeric binder surrounding each semiconductor die may be substantiallyequal. Each discrete portion of the composite frame wafer may containonly one semiconductor die. Each discrete portion of the composite framewafer may be a rectangular solid having approximately 90° cornersbetween adjacent faces thereof. After separating the composite framewafer, additional material may be removed from each of the discreteportions, whereby each portion has a desired shape thereafter. Thecontacts of the at least one semiconductor die in one of the discreteportions may be electrically coupled to spaced-apart conductive traceson a substrate. Electrically coupling the contacts to the conductivetraces may include or consist essentially of adhering the contacts tothe conductive traces with a conductive adhesive, anisotropic conductiveadhesive, and/or solder. The at least one semiconductor die may beelectrically connected to circuitry for powering the at least onesemiconductor die.

Only one semiconductor die may be disposed within each aperture. Theframe wafer may be disposed over the mold substrate after disposing theplurality of semiconductor dies on the mold substrate. The compositeframe wafer may be separated from the mold substrate. A second substratemay be disposed in contact with the composite frame wafer, and the moldsubstrate may be removed from the composite frame wafer, the compositeframe wafer remaining attached to the second substrate. The compositeframe wafer may be separated from the second substrate. Before curingthe polymeric binder, the contacts of the plurality of semiconductordies may be at least partially embedded within the mold substrate. Aftercuring the polymeric binder, at least a portion of each of the contactsof the plurality of semiconductor dies may protrude from the curedbinder. Coating at least a portion of the frame wafer and the pluralityof semiconductor dies with a polymeric binder may include or consistessentially of dispensing the polymeric binder into a mold, anddisposing the mold substrate over the mold, whereby the plurality ofsemiconductor dies are suspended within the polymeric binder. Curing thepolymeric binder may include or consist essentially of at leastpartially curing the polymeric binder, and thereafter, removing the moldsubstrate from the mold. The mold may include or consist essentially ofa plurality of discrete compartments in which the polymeric binder isdisposed. One or more semiconductor dies may be suspended within orabove each compartment prior to curing the polymeric binder. Eachcompartment may impart a complementary shape to a portion of thepolymeric binder. The complementary shapes may be substantiallyidentical to each other. At least one complementary shape may bedifferent from the other complementary shapes.

Coating the plurality of semiconductor dies with the polymeric bindermay include or consist essentially of dispensing the polymeric binderover the mold substrate. Curing the polymeric binder may include orconsist essentially of at least partially curing the polymeric binder,and thereafter, removing the mold substrate from the plurality ofsemiconductor dies. A mold cover may be disposed over and in contactwith at least a portion of the polymeric binder and/or the frame wafer.The mold cover may include or consist essentially of a plurality ofdiscrete compartments. One or more semiconductor dies may be suspendedwithin or beneath each compartment prior to curing the polymeric binder.Each compartment may impart a complementary shape to a portion of thepolymeric binder. The complementary shapes may be substantiallyidentical to each other. At least one complementary shape may bedifferent from the other complementary shapes. The composite frame wafermay have a first surface and a second surface opposite the firstsurface, and a variation in thickness between the first and secondsurfaces may be less than 10%. The thickness of the polymeric binderabove each of the semiconductor dies may be the same to within 5%. Atleast one semiconductor die may include or consist essentially of one ormore active layers (e.g., layers that cooperate to emit or detect light)over a substrate (e.g., a semiconductor substrate), and the substratemay be partially or completely removed before coating with the polymericbinder. The substrate of the at least one semiconductor die may bepartially or completely removed after disposing the at least onesemiconductor die over the mold substrate.

An optical element may be associated with one or more of thesemiconductor dies. An array of optical elements may be disposed over oron the polymeric binder prior to curing. Curing the binder may adherethe array of optical elements to the cured polymeric binder. Thecomposite frame wafer may include the array of optical elements, and thecomposite frame wafer may be separated into discrete portions eachincluding at least one optical element. The sidewall of at least one ofthe apertures may be beveled (i.e., angled with respect to the bottomsurface of the frame and substantially straight). The sidewall of atleast one of the apertures may be contoured (i.e., curved). The topsurface of the frame wafer may be substantially parallel to the bottomsurface of the frame wafer. The polymeric binder may be contained withinthe thickness of the frame wafer. The polymeric binder may extend beyondthe thickness of the frame wafer in a direction away from the bottomsurface of the frame wafer (i.e., toward a top surface of the framewafer and/or toward a top of the aperture). A top surface of thepolymeric binder may be substantially parallel to a face of at least oneof the semiconductor dies. Only a portion of a sidewall of at least oneof the semiconductor dies may protrude from the polymeric binder, asecond portion of the sidewall of the at least one of the semiconductordies being covered with the polymeric binder. The polymeric binder mayinclude, consist essentially of, or consist of silicone and/or epoxy. Atleast one of the semiconductor dies may include, consist essentially of,or consist of a semiconductor material including, consisting essentiallyof, or consisting of GaAs, AlAs, InAs, GaP, AlP, InP, ZnO, CdSe, CdTe,ZnTe, GaN, AlN, InN, silicon, germanium, and/or an alloy or mixturethereof.

At least one of the semiconductor dies may include or consistessentially of a bare-die (i.e., unpackaged) light-emitting diode. Afirst conductive pad may be (i) electrically coupled to one of the twospaced-apart contacts of a semiconductor die and/or (ii) disposed overat least a portion of the bottom surface of the frame wafer. A secondconductive pad may be (i) electrically coupled to the other of the twospaced-apart contacts of the semiconductor die, (ii) electricallyinsulated from the first conductive pad, and/or (iii) disposed over atleast a portion of the bottom surface of the frame wafer. An insulatinglayer may be formed over at least a portion of a surface (e.g., thebottom surface) of the frame wafer. An active and/or a passiveelectronic component may be formed on or over the bottom surface of theframe wafer. The frame wafer may include, consist essentially of, orconsist of a semiconductor material, and the active and/or passiveelectronic component may be formed within or on the semiconductormaterial. The active and/or passive electronic component may include orconsist essentially of a diode (e.g., a Zener diode), a resistor, acapacitor, an inductor, an antenna, and/or a transistor. At least aportion of the sidewall of at least one of the apertures may be texturedor patterned. The frame wafer may include, consist essentially of, orconsist of a semiconductor, a plastic, a polymer, a glass, a ceramic,and/or a metal. The frame wafer may include, consist essentially of, orconsist of silicon and/or gallium arsenide. The plurality of aperturesmay be formed using wet chemical etching, dry chemical etching,ablation, bonding, machining, three-dimensional printing, ultrasonicmachining, abrasive machining, and/or molding. The frame wafer mayinclude, consist essentially of, or consist of a semiconductor material,and the plurality of apertures may be formed using an anisotropic etchprocess. The thickness of the polymeric binder above a firstsemiconductor die may be different from the thickness of the polymericbinder above a second semiconductor die different from the firstsemiconductor die. The polymeric binder may include or consistessentially of a plurality of shaped regions. Each shaped region may beassociated with at least one semiconductor die and/or may have a shapesubstantially identical to shapes of the other shaped regions. Thesidewall of at least one of the apertures may form an angle selectedfrom the range of 15° to 60° with the bottom surface of the frame. Thesemiconductor dies may be arranged in an array having substantiallyequal distances between semiconductor dies in at least a firstdirection. The array of semiconductor dies may be spaced apart atsubstantially equal distances between semiconductor dies in a seconddirection different from the first direction.

In an aspect, embodiments of the invention feature an illuminationdevice including, consisting essentially of, or consisting of apolymeric binder, a bare-die light-emitting element suspended within thepolymeric binder, and a frame. The light-emitting element has (i) afirst face, (ii) a second face opposite the first face, (iii) at leastone sidewall spanning the first and second faces, and (iv) disposed onthe first face of the light-emitting element, at least two spaced-apartcontacts each having a free terminal end. The frame (i) has a bottomsurface, (ii) has a top surface opposite the bottom surface, (iii) has athickness spanning the top and bottom surfaces, and (iv) defines anaperture fully through the thickness. The top surface of the framesurrounds the aperture. The sidewall of the aperture may not beperpendicular to the bottom surface of the frame. The light-emittingelement is disposed within the aperture of the frame such that (i) thesecond face of the light-emitting element is opposite the bottom surfaceof the frame, (ii) the sidewall of the aperture redirects light emittedfrom the light-emitting element away from the bottom surface of theframe, and (iii) the free terminal ends of the contacts of thelight-emitting element are (a) not covered by the polymeric binder and(b) available for electrical connection.

Embodiments of the invention may include one or more of the following inany of a variety of combinations. The sidewall of the aperture may bebeveled (i.e., angled with respect to the bottom surface of the frameand substantially straight). The sidewall of the aperture may becontoured (i.e., curved). The top surface of the frame may besubstantially parallel to the bottom surface of the frame. The polymericbinder may be contained within the thickness of the frame. The polymericbinder may extend beyond the thickness of the frame in a direction awayfrom the bottom surface of the frame. The polymeric binder may have atop surface disposed over the second face of the light-emitting element.The top surface of the polymeric binder may be curved. The top surfaceof the polymeric binder may be substantially flat. The top surface ofthe polymeric binder may be substantially parallel to the first face ofthe light-emitting element. At least portions of the contacts mayprotrude from the polymeric binder. Only a portion of each said sidewallof the light-emitting element may protrude from the polymeric binder, aportion of the sidewall of the light-emitting element being covered withthe polymeric binder. The exterior of the frame may define a hollowrectangular solid having approximately 90° corners between adjacentfaces thereof. The exterior of the frame and the polymeric binder maycollectively define a hollow rectangular solid having approximately 90°corners between adjacent faces thereof.

The polymeric binder may include, consist essentially of, or consist ofsilicone and/or epoxy. One or more additional light-emitting elements(e.g., bare-die light-emitting elements) may be at least partiallysuspended within the polymeric binder. The light-emitting element mayinclude, consist essentially of, or consist of a semiconductor materialincluding, consisting essentially of, or consisting of GaAs, AlAs, InAs,GaP, AlP, InP, ZnO, CdSe, CdTe, ZnTe, GaN, AlN, InN, silicon, germanium,and/or an alloy or mixture thereof. The light-emitting element mayinclude, consist essentially of, or consist of a bare-die light-emittingdiode. The light-emitting element may include, consist essentially of,or consist of active semiconductor layers that are not disposed on asemiconductor substrate. A reflective layer may be disposed over orwithin at least a portion of the polymeric binder. An optical elementmay be positioned to receive light from the light-emitting element. Afirst conductive pad may be electrically coupled to one of the twospaced-apart contacts and/or disposed over at least a portion of thebottom surface of the frame. A second conductive pad may be (i)electrically coupled to the other of the two spaced-apart contacts, (ii)electrically insulated from the first conductive pad, and/or (iii)disposed over at least a portion of the bottom surface of the frame. Theframe may include, consist essentially of, or consist of an electricallyconductive material.

An active and/or a passive electronic component may be disposed over oron the bottom surface of the frame. The frame may include, consistessentially of, or consist of a semiconductor material, and an activeand/or passive electronic component may be disposed within or on thesemiconductor material. The active and/or passive electronic componentmay include, consist essentially of, or consist of a Zener diode, aresistor, a capacitor, an inductor, an antenna, and/or a transistor. Atleast a portion of the sidewall of the aperture may be textured orpatterned. The frame may have at least one exterior face spanning thethickness, and the polymeric binder may be disposed on at least aportion of at least one exterior face of the frame. A second bare-dielight-emitting element may be suspended within the polymeric binder. Thesecond bare-die light-emitting element may have (i) a first face, (ii) asecond face opposite the first face, (iii) at least one sidewallspanning the first and second faces, and (iv) disposed on the first faceof the second light-emitting element, at least two spaced-apart contactseach having a free terminal end. The frame may define a second aperturefully through the thickness of the frame. The second aperture may have asidewall not perpendicular to the bottom surface of the frame. Thesecond light-emitting element may be disposed within the second apertureof the frame such that (i) the second face of the second light-emittingelement is opposite the bottom surface of the frame, (ii) the sidewallof the second aperture redirects light emitted from the secondlight-emitting element away from the bottom surface of the frame, and(iii) the free terminal ends of the contacts of the secondlight-emitting element are (a) not covered by the polymeric binder and(b) available for electrical connection. A wavelength of light emittedby the second light-emitting element may be different from a wavelengthof light emitted by the light-emitting element.

The frame may include, consist essentially of, or consist of asemiconductor, a plastic, a polymer, a glass, a ceramic, and/or a metal.The frame may include, consist essentially of, or consist of siliconand/or gallium arsenide. At least a portion of the sidewall of theaperture (i.e., all or a portion of the frame material itself and/or areflective coating thereon) may be reflective to a wavelength of lightemitted by the light-emitting element. The reflectance of the at least aportion of the sidewall of the aperture may vary with incident angleand/or incident wavelength (i.e., of light incident on the at least aportion of the sidewall of the aperture). The at least a portion of thesidewall of the aperture may have a reflectance greater than 80%, oreven greater than 90%, to a wavelength of light emitted by thelight-emitting element. The at least a portion of the sidewall of theaperture may be a substantially diffuse reflector. The at least aportion of the sidewall of the aperture may be a substantially specularreflector. The at least a portion of the sidewall of the aperture may becoated with a reflective coating that is reflective to a wavelength oflight emitted by the light-emitting element. The reflective coating mayinclude, consist essentially of, or consist of aluminum, silver, gold,silicon dioxide, titanium dioxide, and/or silicon nitride. Thereflective coating may include, consist essentially of, or consist of(i) a reflecting film and/or (ii) a plurality of particles. At least aportion of the polymeric binder may be transparent to a wavelength oflight emitted by the light-emitting element, and the polymeric bindermay contain therein a light-scattering material that scatters thewavelength of light emitted by the light-emitting element.

At least a portion of the polymeric binder may be transparent to awavelength of light emitted by the light-emitting element. The polymericbinder may contain therein a wavelength-conversion material forabsorption of at least a portion of light emitted from thelight-emitting element and emission of converted light having adifferent wavelength, converted light and unconverted light emitted bythe light-emitting element combining to form mixed light. The polymericbinder may include or consist essentially of a plurality of discreteregions, at least one of which includes, consists essentially of, orconsists of the polymeric binder without wavelength-conversion materialtherein. At least a portion of the sidewall of the aperture may becoated with a reflective coating having a reflectance greater than 80%,or even greater than 90%, to a wavelength of light emitted by thelight-emitting element and/or the wavelength-conversion material. Thewavelength-conversion material may include, consist essentially of, orconsist of a phosphor and/or quantum dots.

The mixed light may be substantially white light. The substantiallywhite light may have a correlated color temperature in the range of 2000K to 10,000 K. A maximum divergence of color uniformity of thesubstantially white light in terms of the radially averaged Δu′v′deviation from a spatially weighted average chromaticity may be lessthan 0.01, or even less than 0.006. A divergence of color temperature ofthe substantially white light emitted from the device may vary, over anangular range of 0° to 80°, no more than 0.006 in terms of Δu′v′deviation from a spatially weighted averaged chromaticity. A divergenceof color temperature of the substantially white light emitted from thedevice may vary, over an angular range of 10° to 75°, no more than 0.005in terms of Δu′v′ deviation from a spatially weighted averagedchromaticity. The sidewall of the aperture may form an angle with thebottom surface of the frame, and the angle may be within the range of15° to 60° (inclusive of the end points (here 15° and 60°), as are allranges disclosed herein unless specifically otherwise indicated). Thepolymeric binder may extend above the frame in a direction away from thebottom surface of the frame. The sum of the thickness of the frame and athickness of the polymeric binder extending above the frame may be inthe range of 0.4 mm to 1.8 mm. The ratio of the sum of the thickness ofthe frame and the thickness of the polymeric binder extending above theframe to a lateral dimension of the frame may be in the range of 0.4 to1.8. The ratio of a lateral dimension of the frame (e.g., length, width,or diameter) to a lateral dimension of the light-emitting element (e.g.,length, width, or diameter) may be in the range of 4.1 to 15.9. Theratio of the sum of the thickness of the frame and the thickness of thepolymeric binder extending above the frame to a lateral dimension of thelight-emitting element may be in the range of 0.61 to 2.44. The sidewallof the aperture may form an angle with the bottom surface of the frame,the angle having a value in the range of 15° to 50°, the polymericbinder may extend above the frame in a direction away from the bottomsurface of the frame, and the sum of the thickness of the frame and athickness of the polymeric binder extending above the frame may be inthe range of 0.4 mm to 1.8 mm.

In another aspect, embodiments of the invention feature a compositewafer that includes or consists essentially of a frame wafer, apolymeric binder, and a plurality of bare-die light-emitting elementssuspended within the polymeric binder. The frame wafer (i) has a bottomsurface, (ii) has a top surface opposite the bottom surface, (iii) has athickness spanning the top and bottom surfaces, and (iv) defines aplurality of apertures (a) each extending fully through the thicknessand (b) each having a sidewall. The top surface of the frame wafersurrounds each aperture. One or more (or even each) of the apertures mayhave a sidewall not perpendicular to the bottom surface of the frame.The polymeric binder is disposed within at least a portion of each ofthe plurality of apertures (i.e., as a continuous connected volumehaving portions in each of the apertures, or as a plurality ofindividual unconnected volumes each in one of the apertures). Eachlight-emitting element has (i) a first face, (ii) a second face oppositethe first face, (iii) at least one sidewall spanning the first andsecond faces, and (iv) disposed on the first face of the light-emittingelement, at least two spaced-apart contacts each having a free terminalend. The second face of each light-emitting element is opposite thebottom surface of the frame. The sidewall of each aperture redirectslight emitted from a light-emitting element away from the bottom surfaceof the frame. The free terminal ends of the contacts of eachlight-emitting element are (a) not covered by the polymeric binder and(b) available for electrical connection.

Embodiments of the invention may include one or more of the following inany of a variety of combinations. The sidewall of at least one aperturemay be beveled (i.e., angled with respect to the bottom surface of theframe and substantially straight). The sidewall of at least one aperturemay be contoured (i.e., curved). The top surface of the frame wafer maybe substantially parallel to the bottom surface of the frame wafer. Thepolymeric binder may be contained within the thickness of the framewafer. The polymeric binder may extend beyond the thickness of the framewafer in a direction opposite the bottom surface of the frame wafer. Thepolymeric binder may have a top surface disposed over the light-emittingelements. At least a portion of the top surface of the polymeric bindermay be curved (e.g., a portion of the top surface of the binder overeach light-emitting element may be curved, and portions betweenapertures of the frame may be substantially flat or may simply be whereindividual curved portions meet). At least a portion of the top surfaceof the polymeric binder may be substantially flat. At least a portion ofthe top surface of the polymeric binder may be substantially parallel tothe first face of at least one light-emitting element. At least portionsof the contacts of the light-emitting elements may protrude from thepolymeric binder. Only a portion of each said sidewall of at least onelight-emitting element may protrude from the polymeric binder, and asecond portion of each said sidewall of the at least one light-emittingelement may be covered with the polymeric binder. The polymeric bindermay include, consist essentially of, or consist of silicone and/orepoxy.

At least one light-emitting element may include, consist essentially of,or consist of a semiconductor material including, consisting essentiallyof, or consisting of GaAs, AlAs, InAs, GaP, AlP, InP, ZnO, CdSe, CdTe,ZnTe, GaN, AlN, InN, silicon, germanium, and/or an alloy or mixturethereof. At least one light-emitting element may include, consistessentially of, or consist of a (bare-die) light-emitting diode. Atleast one light-emitting element may include, consist essentially of, orconsist of active semiconductor layers that are not disposed on asemiconductor substrate. A reflective layer may be disposed over orwithin at least a portion of the polymeric binder. An optical elementmay be positioned to receive light from at least one light-emittingelement. A first conductive pad may be (i) electrically coupled to oneof the two spaced-apart contacts of a light-emitting element and/or (ii)disposed over at least a portion of the bottom surface of the framewafer. A second conductive pad may be (i) electrically coupled to theother of the two spaced-apart contacts of the light-emitting element,(ii) electrically insulated from the first conductive pad, and/or (iii)disposed over at least a portion of the bottom surface of the framewafer. The frame wafer may include, consist essentially of, or consistof an electrically conductive material. An insulating layer may bedisposed over at least a portion of a surface of the frame wafer. Anactive and/or a passive electronic component may be disposed over or onthe bottom surface of the frame wafer. The frame wafer may include,consist essentially of, or consist of a semiconductor material, and anactive and/or a passive electronic component may be disposed withinand/or on the semiconductor material. The active and/or passiveelectronic component may include, consist essentially of, or consist ofa diode (e.g., a Zener diode), a resistor, a capacitor, an inductor, anantenna, and/or a transistor.

At least a portion of the sidewall of at least one aperture may betextured or patterned. The frame wafer may include, consist essentiallyof, or consist of a semiconductor, a plastic, a polymer, a glass, aceramic, and/or a metal. The frame wafer may include, consistessentially of, or consist of silicon and/or gallium arsenide. At leasta portion of the sidewall of at least one aperture (i.e., at least aportion of the frame wafer material itself and/or a reflective coatingdisposed on the sidewall of the at least one aperture) may be reflectiveto a wavelength of light emitted by at least one light-emitting element(e.g., a light-emitting element disposed within the aperture). Thereflectance of the at least a portion of the sidewall of at least oneaperture may vary with incident angle and/or incident wavelength. The atleast a portion of the sidewall of at least one aperture may have areflectance greater than 80%, or even greater than 90%, to a wavelengthof light emitted by at least one light-emitting element. The at least aportion of the sidewall of at least one aperture may be a substantiallydiffuse reflector. The at least a portion of the sidewall of at leastone aperture may be a substantially specular reflector. The at least aportion of the sidewall of at least one aperture may be coated with areflective coating that is reflective to a wavelength of light emittedby at least one light-emitting element (e.g., a light-emitting elementdisposed within the aperture). The reflective coating may include,consist essentially of, or consist of aluminum, silver, gold, silicondioxide, titanium dioxide, and/or silicon nitride. The reflectivecoating may include, consist essentially of, or consist of (i) areflecting film and/or (ii) a plurality of particles.

At least a portion of the polymeric binder may be transparent to awavelength of light emitted by at least one light-emitting element. Thepolymeric binder may contain therein a wavelength-conversion materialfor absorption of at least a portion of light emitted from the at leastone light-emitting element and emission of converted light having adifferent wavelength, and converted light and unconverted light emittedby the at least one light-emitting element may combine to form mixedlight. The wavelength-conversion material may include, consistessentially of, or consist of a phosphor and/or quantum dots. Thepolymeric binder may include, consist essentially of, or consist of aplurality of discrete regions, at least one of which may include,consist essentially of, or consist of the polymeric binder withoutwavelength-conversion material therein. At least a portion of thesidewall of at least one aperture may be coated with reflective coatinghaving a reflectance greater than 80%, or even greater than 90%, to awavelength of light emitted by at least one light-emitting elementand/or the wavelength-conversion material. The mixed light may besubstantially white light. The substantially white light may have acorrelated color temperature in the range of 2000 K to 10,000 K. Themaximum divergence of color uniformity of the substantially white lightin terms of the radially averaged Δu′v′ deviation from the spatiallyweighted average chromaticity may be less than 0.01, or even less than0.006. The divergence of color temperature of the substantially whitelight may vary, over an angular range of 0° to 80°, no more than 0.006in terms of Δu′v′ deviation from a spatially weighted averagedchromaticity. The divergence of color temperature of the substantiallywhite light may vary, over an angular range of 10° to 75°, no more than0.005 in terms of Δu′v′ deviation from a spatially weighted averagedchromaticity. The variation in color temperature of the substantiallywhite light emitted when each light-emitting element is individuallyenergized may be less than 500 K, or even less than 250 K. The variationin color temperature of the substantially white light emitted when eachlight-emitting element is individually energized may be less than fourMacAdam ellipses, less than three MacAdam ellipses, or even less thantwo MacAdam ellipses.

A thickness of the polymeric binder disposed above each of the pluralityof light-emitting elements may be the same to within 5%. Thelight-emitting elements may be arranged in an array having substantiallyequal distances between light-emitting elements in at least a firstdirection. The array of light-emitting elements may be spaced apart atsubstantially equal distances between light-emitting elements in asecond direction different from the first direction. A thickness of thepolymeric binder above a first light-emitting element may be differentfrom a thickness of the polymeric binder above a second light-emittingelement different from the first light-emitting element. The polymericbinder may include, consist essentially of, or consist of a plurality ofshaped regions. Each shaped region may be associated with at least onelight-emitting element. Each shaped region may have a shapesubstantially identical to shapes of the other shaped regions. At leastone shaped region may have a shape different from shapes of the othershaped regions.

In another aspect, embodiments of the invention feature an electronicdevice that includes or consists essentially of a polymeric binder, asemiconductor die suspended within the polymeric binder, and a frame.The semiconductor die has a (i) first face, (ii) a second face oppositethe first face, and (iii) at least one sidewall spanning the first andsecond faces. The semiconductor die is a bare-die light-detectingelement including or consisting essentially of at least onesemiconductor layer configured to absorb light over a detectedwavelength range and produce electrical charge therefrom. At least twospaced-apart contacts are disposed on the first face of thesemiconductor die. Each contact (i) has a free terminal end not coveredby the polymeric binder, and (ii) is available for electricalconnection. The contacts may each be (e.g., electrically) connected to adifferent semiconductor layer of the semiconductor die, or the contactsmay contact the same semiconductor layer. For example, if thesemiconductor die includes or consists essentially of a Schottky diode,two contacts may make contact to the same semiconductor layer—onecontact may form an ohmic contact with the layer, and the other contactmay form a rectifying contact with the layer. The frame (i) has a bottomsurface, (ii) has a top surface opposite the bottom surface, (iii) has athickness spanning the top and bottom surfaces, and (iv) defines anaperture (a) extending fully through the thickness and (b) having asidewall. The top surface of the frame surrounds the aperture. Thesidewall of the aperture may not be perpendicular to the bottom surfaceof the frame. At least a portion of the polymeric binder is transparentto a wavelength of light within the detected wavelength range. Thesemiconductor die is disposed within the aperture of the frame such that(i) the second face of the semiconductor die is opposite the bottomsurface of the frame, (ii) the sidewall of the aperture redirects lighttoward the semiconductor die, and (iii) the free terminal ends of thecontacts of the semiconductor die are (a) not covered by the polymericbinder and (b) available for electrical connection.

Embodiments of the invention may include one or more of the following inany of a variety of combinations. The polymeric binder may containtherein a wavelength-conversion material for absorption of at least aportion of light incident on the electronic device and emission ofconverted light having a different wavelength (e.g., emitted at leastpartially toward the semiconductor die). Substantially all of the lightabsorbed by the light-detecting element may be converted light. Thedifferent wavelength of the converted light may be within the detectedwavelength range. The wavelength-conversion material may include,consist essentially of, or consist of a phosphor and/or quantum dots.The polymeric binder may include, consist essentially of, or consist ofa plurality of discrete regions. At least one of the discrete regionsmay include, consist essentially of, or consist of the polymeric binderwithout wavelength-conversion material therein. At least a portion ofthe sidewall of the aperture may be reflective to a wavelength of lightwithin the detected wavelength range and/or light emitted by thewavelength-conversion material. The reflectance of the at least aportion of the sidewall of the aperture may vary with incident angleand/or incident wavelength. The at least a portion of the sidewall ofthe aperture may have a reflectance greater than 80%, or even greaterthan 90%, to a wavelength of light within the detected wavelength rangeand/or light emitted by the wavelength-conversion material. The at leasta portion of the sidewall of the aperture may be a substantially diffusereflector. The at least a portion of the sidewall of the aperture may bea substantially specular reflector. The at least a portion of thesidewall of the aperture may be coated with a reflective coating that isreflective to a wavelength of light within the detected wavelength rangeand/or light emitted by the wavelength-conversion material. Thereflective coating may include, consist essentially of, or consist ofaluminum, silver, gold, silicon dioxide, titanium dioxide, and/orsilicon nitride. The reflective coating may include, consist essentiallyof, or consist of (i) a reflecting film and/or (ii) a plurality ofparticles.

The polymeric binder may include therein an absorbing material forabsorption of at least a portion of the spectrum of light incident uponthe electronic device (e.g., upon the semiconductor die and/or upon thepolymeric binder). A wavelength of the portion of the spectrum of lightabsorbed by the absorbing material may be within the detected wavelengthrange. A wavelength of the portion of the spectrum of light absorbed bythe absorbing material may be longer or shorter than the detectedwavelength range. The polymeric binder may include, consist essentiallyof, or consist of a plurality of discrete regions, at least one of whichmay include, consist essentially of, or consist of the polymeric binderwithout the absorbing material therein. The polymeric binder may includetherein a reflective material for reflection of at least a portion ofthe spectrum of light incident upon electronic device (e.g., upon thesemiconductor die and/or upon the polymeric binder). A wavelength of theportion of the spectrum of light reflected by the reflective materialmay be within the detected wavelength range. The polymeric binder mayinclude, consist essentially of, or consist of a plurality of discreteregions, at least one of which may include, consist essentially of, orconsist of the polymeric binder without the reflective material therein.The semiconductor die may include, consist essentially of, or consist ofa bare-die photovoltaic cell. The semiconductor die may include, consistessentially of, or consist of a bare-die photovoltaic cell, a bare-dieinfrared detector, a bare-die ultraviolet detector, a bare-die visiblelight detector, and/or a bare-die x-ray detector. The semiconductor diemay include, consist essentially of, or consist of a p-n junction, aSchottky junction, a photoelectric detector, a photocell, aphotoresistor, a photodiode, a phototransistor, a charge-coupled device,and/or a bare-die imaging chip.

The sidewall of the aperture (or one or more portions thereof) may bebeveled or contoured. The top surface of the frame may be substantiallyparallel to the bottom surface of the frame. The polymeric binder may becontained within the thickness of the frame. The polymeric binder mayextend beyond the thickness of the frame in a direction away from thebottom face of the frame. The polymeric binder may have a top surfacedisposed over the light-detecting element. The top surface of thepolymeric binder may be curved or substantially flat. The top surface ofthe polymeric binder may be substantially parallel to the first face ofthe semiconductor die. At least portions of the contacts may protrudefrom the polymeric binder. Only a portion of each said sidewall of thesemiconductor die may protrude from the polymeric binder, and a portionof each said sidewall of the semiconductor die may be covered with thepolymeric binder. An exterior of the frame may define a (hollow)rectangular solid having approximately 90° corners between adjacentfaces thereof. The polymeric binder may include, consist essentially of,or consist of silicone and/or epoxy. One or more additionalsemiconductor dies (e.g., one or more bare-die light-detecting elements,each of which may (but do not necessarily) detect light over a differentwavelength range) may be suspended within the polymeric binder. Thelight-detecting element may include, consist essentially of, or consistof a semiconductor material that includes, consists essentially of, orconsists of GaAs, AlAs, InAs, GaP, AlP, InP, ZnO, CdSe, CdTe, ZnTe, GaN,AlN, InN, silicon, germanium, and/or an alloy or mixture thereof. Thelight-detecting element may include, consist essentially of, or consistof one or more active semiconductor layers that are not disposed on asemiconductor substrate. A reflective layer may be disposed over orwithin at least a portion of the polymeric binder. An optical element(e.g., a lens) may be positioned to couple light to the semiconductordie.

A first conductive pad may be electrically coupled to one of the twospaced-apart contacts and/or disposed over at least a portion of thebottom surface of the frame. A second conductive pad may be (i)electrically coupled to the other of the two spaced-apart contacts, (ii)electrically insulated from the first conductive pad, and/or (iii)disposed over at least a portion of the bottom surface of the frame. Theframe may include, consist essentially of, or consist of an electricallyconductive material. An insulating layer may be disposed over or on atleast a portion of a surface of the frame. One or more active and/orpassive electronic components may be disposed over or on the bottomsurface of the frame. The frame may include, consist essentially of, orconsist of a semiconductor material, and one or more active and/orpassive electronic components may be formed within or on thesemiconductor material. The active and/or passive electronic componentmay include, consist essentially of, or consist of a Zener diode, aresistor, a capacitor, an inductor, an antenna, and/or a transistor. Atleast a portion of the sidewall of the aperture may be textured orpatterned. The frame may have at least one exterior face spanning thethickness of the frame, and the polymeric binder may be disposed on atleast a portion of at least one exterior face of the frame.

A second bare-die light-detecting element may be suspended within thepolymeric binder. The second bare-die light-detecting element may have(i) a first face, (ii) a second face opposite the first face, (iii) atleast one sidewall spanning the first and second faces, and (iv)disposed on the first face of the second light-detecting element, atleast two spaced-apart contacts each having a free terminal end. Theframe may define a second aperture fully through the thickness of theframe, and the second aperture may have a sidewall not perpendicular tothe bottom surface of the frame. The second light-detecting element maybe disposed within the second aperture of the frame such that (i) thesecond face of the second light-detecting element is opposite the bottomsurface of the frame, (ii) the sidewall of the second aperture redirectslight toward the second light-detecting element, and (iii) the freeterminal ends of the contacts of the second light-detecting element are(a) not covered by the polymeric binder and (b) available for electricalconnection. The detected wavelength range of the bare-dielight-detecting element may be different from a detected wavelengthrange of second bare-die light-detecting element. The second bare-dielight-detecting element may include, consist essentially of, or consistof at least one semiconductor layer configured to absorb light over thedetected wavelength range of second bare-die light-detecting element.The frame may include, consist essentially of, or consist of asemiconductor, a plastic, a polymer, a glass, a ceramic, and/or a metal.The frame may include, consist essentially of, or consist of siliconand/or gallium arsenide.

At least a portion of the sidewall of the aperture (i.e., all or aportion of the frame material itself and/or a reflective coatingthereon) may be reflective to a wavelength of light within the detectedwavelength range. The reflectance of the at least a portion of thesidewall of the aperture may vary with incident angle and/or incidentwavelength. The at least a portion of the sidewall of the aperture mayhave a reflectance greater than 80%, or even greater than 90%, to awavelength of light within the detected wavelength range. The at least aportion of the sidewall of the aperture may be a substantially diffusereflector. The at least a portion of the sidewall of the aperture may bea substantially specular reflector. The at least a portion of thesidewall of the aperture may be coated with a reflective coating that isreflective to a wavelength of light within the detected wavelengthrange. The reflective coating may include, consist essentially of, orconsist of aluminum, silver, gold, silicon dioxide, titanium dioxide,and/or silicon nitride. The reflective coating may include, consistessentially of, or consist of (i) a reflecting film and/or (ii) aplurality of particles. The frame may be substantially transparent to awavelength of light within the detected wavelength range. A reflectivelayer may be disposed on at least a portion of a surface (e.g., anexterior surface facing away from the aperture, the bottom surface, thetop surface, and/or all or part of the sidewall of the aperture) of theframe.

In another aspect, embodiments of the invention feature an electronicdevice that includes or consists essentially of a polymeric binder, asemiconductor die suspended within the polymeric binder, and a frame.The semiconductor die has (i) a first face, (ii) a second face oppositethe first face, (iii) at least one sidewall spanning the first andsecond faces, and (iv) disposed on the first face of the semiconductordie, at least two spaced-apart contacts each having a free terminal end.The frame (i) has a bottom surface, (ii) has a top surface opposite thebottom surface, (iii) has a thickness spanning the top and bottomsurfaces, and (iv) defines an aperture (a) extending fully through thethickness and (b) having a sidewall. The top surface of the framesurrounds the aperture. The sidewall of the aperture may not beperpendicular to the bottom surface of the frame. The semiconductor dieis disposed within the aperture of the frame such that (i) the secondface of the semiconductor die is opposite the bottom surface of theframe, and (ii) the free terminal ends of the contacts of thesemiconductor die are (a) not covered by the polymeric binder and (b)available for electrical connection.

In another aspect, embodiments of the invention feature a compositewafer including or consisting essentially of a frame wafer, a polymericbinder, and a plurality of semiconductor dies suspended in the polymericbinder. The frame wafer (i) has a bottom surface, (ii) has a top surfaceopposite the bottom surface, (iii) has a thickness spanning the top andbottom surfaces, and (iv) defines a plurality of apertures (a) eachextending fully through the thickness and (b) each having a sidewall.The top surface of the frame wafer surrounds each aperture. The sidewallof at least one of the apertures may not be perpendicular to the bottomsurface of the frame wafer. The polymeric binder is disposed within atleast a portion of each of the plurality of apertures. Eachsemiconductor die has (i) a first face, (ii) a second face opposite thefirst face, (iii) at least one sidewall spanning the first and secondfaces, and (iv) disposed on the first face of the semiconductor die, atleast two spaced-apart contacts each having a free terminal end. Thesecond face of each semiconductor die is opposite the bottom surface ofthe frame, and the free terminal ends of the contacts of eachsemiconductor die are (a) not covered by the polymeric binder and (b)available for electrical connection.

In yet another aspect, embodiments of the invention feature anillumination device that includes or consists essentially of a polymericbinder, a bare-die light-emitting element suspended within the polymericbinder, and a frame. The bare-die light-emitting element has (i) a firstface, (ii) a second face opposite the first face, (iii) at least onesidewall spanning the first and second faces, and (iv) disposed on thefirst face of the light-emitting element, at least two spaced-apartcontacts each having a free terminal end. The frame (i) has a bottomsurface, (ii) has a top surface opposite the bottom surface, (iii) has athickness spanning the top and bottom surfaces, and (iv) defines anaperture (a) extending fully through the thickness and (b) having asidewall. The top surface of the frame surrounds the aperture. Thesidewall of the aperture may not be perpendicular to the bottom surfaceof the frame. At least a portion of the frame is substantiallytransparent to a wavelength of light emitted by the light-emittingelement. The light-emitting element is disposed within the aperture ofthe frame such that (i) the second face of the light-emitting element isopposite the bottom surface of the frame, and (ii) the free terminalends of the contacts of the light-emitting element are (a) not coveredby the polymeric binder and (b) available for electrical connection.

Embodiments of the invention may include one or more of the following inany of a variety of combinations. The sidewall of the aperture mayredirect light emitted from the light-emitting element. An index ofrefraction of the frame may be substantially the same as an index ofrefraction of the polymeric binder. A reflective layer may be disposedon at least a portion of a surface of the frame (e.g., an exteriorsurface facing away from the aperture, the bottom surface, the topsurface, and/or all or part of the sidewall of the aperture). Thereflective layer may be a substantially diffuse reflector. Thereflective layer may be a substantially specular reflector. Thereflective layer may include, consist essentially of, or consist ofaluminum, silver, gold, silicon dioxide, titanium dioxide, and/orsilicon nitride. The reflective layer may include, consist essentiallyof, or consist of (i) a reflecting film and/or (ii) a plurality ofparticles. The reflective layer may have a reflectance greater than 80%,or even greater than 90%, to a wavelength of light emitted by thelight-emitting element. At least a portion of the reflective layer mayhave a reflectance that varies with incident angle and/or incidentwavelength. The top surface of the frame may be substantially parallelto the bottom surface of the frame. The polymeric binder may becontained within the thickness of the frame. The polymeric binder mayextend beyond the thickness of the frame in a direction away from thebottom face of the frame. The polymeric binder may have a top surfacedisposed over the second face the light-emitting element. All or part ofthe top surface of the polymeric binder may be curved or substantiallyflat. The top surface of the polymeric binder may be substantiallyparallel to the first face of the light-emitting element. At leastportions of the contacts may protrude from the polymeric binder. Only aportion of each said sidewall of the light-emitting element may protrudefrom the polymeric binder, and a portion of each said sidewall of thelight-emitting element may be covered with the polymeric binder.

An exterior of the frame may define a rectangular solid (i.e., a hollowrectangular solid) having approximately 90° corners between adjacentfaces thereof. The polymeric binder may include, consist essentially of,or consist of silicone and/or epoxy. One or more additional bare-dielight-emitting elements may be at least partially suspended within thepolymeric binder. The light-emitting element may include, consistessentially of, or consist of a semiconductor material including,consisting essentially of, or consisting of GaAs, AlAs, InAs, GaP, AlP,InP, ZnO, CdSe, CdTe, ZnTe, GaN, AlN, InN, silicon, germanium, and/or analloy or mixture thereof. The light-emitting element may include,consist essentially of, or consist of a light-emitting diode. Thelight-emitting element may include, consist essentially of, or consistof one or more active semiconductor layers that are not disposed on asemiconductor substrate. A reflective layer may be disposed over and/orwithin at least a portion of the polymeric binder. An optical elementmay be positioned to receive light from the light-emitting element. Afirst conductive pad may be electrically coupled to one of the twospaced-apart contacts and/or disposed over at least a portion of thebottom surface of the frame. A second conductive pad may be (i)electrically coupled to the other of the two spaced-apart contacts, (ii)electrically insulated from the first conductive pad, and/or (iii)disposed over at least a portion of the bottom surface of the frame. Theframe may include, consist essentially of, or consist of an electricallyconductive material. An insulating layer may be disposed over at least aportion of the surface of the frame.

One or more active and/or passive electronic components may be disposedover or on the bottom surface of the frame. The frame may include,consist essentially of, or consist of a semiconductor material, and oneor more active and/or passive electronic components (e.g., a Zenerdiode, a resistor, a capacitor, an inductor, an antenna, and/or atransistor) may be disposed within or on the semiconductor material. Atleast a portion of the sidewall of the aperture may be textured orpatterned. The frame may have at least one exterior face spanning thethickness, and a portion of the polymeric binder may be disposed on atleast a portion of at least one exterior face of the frame. A secondbare-die light-emitting element may be suspended within the polymericbinder. The second bare-die light-emitting element may have (i) a firstface, (ii) a second face opposite the first face, (iii) at least onesidewall spanning the first and second faces, and (iv) disposed on thefirst face of the light-emitting element, at least two spaced-apartcontacts each having a free terminal end. The frame may define a secondaperture fully through the thickness of the frame, and the secondaperture may have a sidewall not perpendicular to the bottom surface ofthe frame. The second light-emitting element may be disposed within thesecond aperture of the frame such that (i) the second face of the secondlight-emitting element is opposite the bottom surface of the frame, and(ii) the free terminal ends of the contacts of the second light-emittingelement are (a) not covered by the polymeric binder and (b) availablefor electrical connection. A wavelength of light emitted by the secondlight-emitting element may be different from a wavelength of lightemitted by the light-emitting element.

The frame may include, consist essentially of, or consist of asemiconductor, a plastic, a polymer, a glass, a ceramic, and/or a metal.The frame may include, consist essentially of, or consist of siliconand/or gallium arsenide. At least a portion of the sidewall of theaperture may be reflective to a wavelength of light emitted by thelight-emitting element. The reflectance of the at least a portion of thesidewall of the aperture may vary with incident angle and/or incidentwavelength. The at least a portion of the sidewall of the aperture mayhave a reflectance greater than 80%, or even greater than 90%, to awavelength of light emitted by the light-emitting element. The at leasta portion of the sidewall of the aperture may be a substantially diffusereflector. The at least a portion of the sidewall of the aperture may bea substantially specular reflector. The at least a portion of thesidewall of the aperture may include, consist essentially of, or consistof aluminum, silver, gold, silicon dioxide, titanium dioxide, and/orsilicon nitride. The at least a portion of the sidewall of the aperturemay be coated with a reflective coating that is reflective to awavelength of light emitted by the light-emitting element. Thereflective coating may include, consist essentially of, or consist of(i) a reflecting film and/or (ii) a plurality of particles.

At least a portion of the polymeric binder may be transparent to awavelength of light emitted by the light-emitting element. The polymericbinder may contain therein a wavelength-conversion material forabsorption of at least a portion of light emitted from thelight-emitting element and emission of converted light having adifferent wavelength, and converted light and unconverted light emittedby the light-emitting element may combine to form mixed light. Thewavelength-conversion material may include, consist essentially of, orconsist of a phosphor and/or quantum dots. The mixed light may besubstantially white light. The substantially white light may have acorrelated color temperature in the range of 2000 K to 10,000 K. Areflective layer may be disposed on at least a portion of a surface ofthe frame (e.g., an exterior surface facing away from the aperture, thebottom surface, the top surface, and/or all or part of the sidewall ofthe aperture). The reflective layer may be a substantially diffusereflector. The reflective layer may be a substantially specularreflector. The reflective layer may include, consist essentially of, orconsist of aluminum, silver, gold, silicon dioxide, titanium dioxide,and/or silicon nitride. The reflective layer may include, consistessentially of, or consist of (i) a reflecting film and/or (ii) aplurality of particles. The reflective layer may have a reflectancegreater than 80%, or even greater than 90%, to a wavelength of lightemitted by the light-emitting element. At least a portion of thereflective layer may have a reflectance that varies with incident angleand/or incident wavelength.

The maximum divergence of color uniformity of the substantially whitelight in terms of the radially averaged Δu′v′ deviation from a spatiallyweighted average chromaticity may be less than 0.01, or even less than0.006. The polymeric binder may include, consist essentially of, orconsist of a plurality of discrete regions. At least one of the discreteregions may include, consist essentially of, or consist of the polymericbinder without wavelength-conversion material therein. At least aportion of the sidewall of the aperture may be coated with reflectivecoating having a reflectance greater than 80%, or even greater than 90%,to a wavelength of light emitted by the light-emitting element and/orthe wavelength-conversion material.

At least a portion of the polymeric binder may be transparent to awavelength of light emitted by the light-emitting element. The polymericbinder may contain therein light-scattering material that scatters awavelength of light emitted by the light-emitting element. Thedivergence of color temperature of the substantially white light emittedfrom the device may vary, over an angular range of 0° to 80°, no morethan 0.006 in terms of Δu′v′ deviation from a spatially weightedaveraged chromaticity. The divergence of color temperature of thesubstantially white light emitted from the device may vary, over anangular range of 10° to 75°, no more than 0.005 in terms of Δu′v′deviation from a spatially weighted averaged chromaticity. The sidewallof the aperture may form an angle with the bottom surface of the frame,the angle having a value in the range of 15° to 60°. The polymericbinder may extend above the frame in a direction away from the bottomsurface of the frame. The sum of the thickness of the frame and thethickness of the polymeric binder extending above the frame may be inthe range of 0.4 mm to 1.8 mm. The ratio of the sum of the thickness ofthe frame and the thickness of the polymeric binder extending above theframe to a lateral dimension (e.g., length, width, or diameter) of theframe may be in the range of 0.4 to 1.8. The ratio of a lateraldimension of the frame to a lateral dimension of the light-emittingelement may be in the range of 4.1 to 15.9. The ratio of the sum of thethickness of the frame and the thickness of the polymeric binderextending above the frame to a lateral dimension of the light-emittingelement may be in the range of 0.61 to 2.44. The sidewall of theaperture may form an angle with the bottom surface of the frame, theangle having a value in the range of 15° to 50°, the polymeric bindermay extend above the frame in a direction away from the bottom surfaceof the frame, and the sum of the thickness of the frame and thethickness of the phosphor extending above the frame may be in the rangeof 0.4 mm to 1.8 mm.

As utilized herein, the term “light-emitting element” (LEE) refers toany device that emits electromagnetic radiation within a wavelengthregime of interest, for example, visible, infrared or ultravioletregime, when activated, by applying a potential difference across thedevice or passing a current through the device. Examples of LEEs includesolid-state, organic, polymer, phosphor-coated or high-flux LEDs,microLEDs (described below), laser diodes or other similar devices aswould be readily understood. The emitted radiation of a LEE may bevisible, such as red, blue or green, or invisible, such as infrared orultraviolet. A LEE may produce radiation of a spread of wavelengths. ALEE may feature a phosphorescent or fluorescent material for convertinga portion of its emissions from one set of wavelengths to another. A LEEmay include multiple LEEs, each emitting essentially the same ordifferent wavelengths. In some embodiments, a LEE is an LED that mayfeature a reflector over all or a portion of its surface upon whichelectrical contacts are positioned. The reflector may also be formedover all or a portion of the contacts themselves. In some embodiments,the contacts are themselves reflective.

An LEE may be of any size. In some embodiments, an LEE has one lateraldimension less than 500 μm, while in other embodiments an LEE has onelateral dimension greater than 500 μm. Exemplary sizes of a relativelysmall LEE may include about 175 μm by about 250 μm, about 250 μm byabout 400 μm, about 250 μm by about 300 μm, or about 225 μm by about 175μm. Exemplary sizes of a relatively large LEE may include about 1000 μmby about 1000 μm, about 500 μm by about 500 μm, about 250 μm by about600 μm, or about 1500 μm by about 1500 μm. In some embodiments, an LEEincludes or consists essentially of a small LED die, also referred to asa “microLED.” A microLED generally has one lateral dimension less thanabout 300 μm. In some embodiments, the LEE has one lateral dimensionless than about 200 μm or even less than about 100 μm. For example, amicroLED may have a size of about 225 μm by about 175 μm or about 150 μmby about 100 μm or about 150 μm by about 50 μm. In some embodiments, thesurface area of the top surface of a microLED is less than 50,000 μm² orless than 10,000 μm². The size of the LEE is not a limitation of thepresent invention, and in other embodiments the LEE may be relativelylarger, e.g., the LEE may have one lateral dimension on the order of atleast about 1000 μm or at least about 3000 μm.

As used herein, “phosphor” refers to any material that shifts thewavelengths of light irradiating it and/or that is fluorescent and/orphosphorescent. As used herein, a “phosphor” may refer to only thepowder or particles (of one or more different types) or to the powder orparticles with the binder, and in some circumstances may refer toregion(s) containing only the binder (for example, in a remote-phosphorconfiguration in which the phosphor is spaced away from the LEE). Theterms “wavelength-conversion material” and “light-conversion material”are utilized interchangeably with “phosphor” herein. Thelight-conversion material is incorporated to shift one or morewavelengths of at least a portion of the light emitted by LEEs to other(i.e., different) desired wavelengths (which are then emitted from thelarger device alone or color-mixed with another portion of the originallight emitted by the LEE). A light-conversion material may include orconsist essentially of phosphor powders, quantum dots or the like withina transparent binder. Phosphors are typically available in the form ofpowders or particles, and in such case may be mixed in binders. Anexemplary binder is silicone, i.e., polyorganosiloxane, which is mostcommonly polydimethylsiloxane (PDMS). Phosphors vary in composition, andmay include lutetium aluminum garnet (LuAG or GAL), yttrium aluminumgarnet (YAG) or other phosphors known in the art. GAL, LuAG, YAG andother materials may be doped with various materials including forexample Ce, Eu, etc. The specific components and/or formulation of thephosphor and/or matrix material are not limitations of the presentinvention.

The binder may also be referred to as an encapsulant or a matrixmaterial. In one embodiment, the binder includes or consists essentiallyof a transparent material, for example silicone-based materials orepoxy, having an index of refraction greater than 1.35. In oneembodiment the binder and/or phosphor includes or consists essentiallyof other materials, for example fumed silica or alumina, to achieveother properties, for example to scatter light, or to reduce settling ofthe powder in the binder. An example of the binder material includesmaterials from the ASP series of silicone phenyls manufactured by ShinEtsu, or the Sylgard series manufactured by Dow Corning. In oneembodiment the binder may be glass or ceramic material, or a lowtemperature glass or ceramic material.

Herein, two components such as light-emitting elements and/or opticalelements being “aligned” or “associated” with each other may refer tosuch components being mechanically and/or optically aligned. By“mechanically aligned” is meant coaxial or situated along a parallelaxis. By “optically aligned” is meant that at least some light (or otherelectromagnetic signal) emitted by or passing through one componentpasses through and/or is emitted by the other.

Various embodiments of the present invention also incorporate features,and/or are fabricated at least in part in accordance with techniques,described in U.S. patent application Ser. No. 13/748,864, filed Jan. 24,2013 (the '864 application), U.S. patent application Ser. No.13/949,543, filed Jul. 24, 2013 (the '543 application), U.S. patentapplication Ser. No. 13/828,498, filed Mar. 14, 2013, U.S. patentapplication Ser. No. 13/770,432, filed Feb. 19, 2013, and U.S. patentapplication Ser. No. 14/166,329, filed Jan. 28, 2014, the entiredisclosure of each of which is incorporated by reference herein.

These and other objects, along with advantages and features of theinvention, will become more apparent through reference to the followingdescription, the accompanying drawings, and the claims. Furthermore, itis to be understood that the features of the various embodimentsdescribed herein are not mutually exclusive and may exist in variouscombinations and permutations. Reference throughout this specificationto “one example,” “an example,” “one embodiment,” or “an embodiment”means that a particular feature, structure, or characteristic describedin connection with the example is included in at least one example ofthe present technology. Thus, the occurrences of the phrases “in oneexample,” “in an example,” “one embodiment,” or “an embodiment” invarious places throughout this specification are not necessarily allreferring to the same example. Furthermore, the particular features,structures, routines, steps, or characteristics may be combined in anysuitable manner in one or more examples of the technology. The term“light” broadly connotes any wavelength or wavelength band in theelectromagnetic spectrum, including, without limitation, visible light,ultraviolet radiation, infrared, mid-infrared, and far infraredradiation. Similarly, photometric terms such as “illuminance,” “luminousflux,” and “luminous intensity” extend to and include their radiometricequivalents, such as “irradiance,” “radiant flux,” and “radiantintensity.” Light produced by light-emitting devices (e.g., frame diesor composite wafers) in accordance with embodiments of the presentinvention may be white or any other color that is produced by one ormore light emitters and/or one or more light-conversion materials. Asused herein, the terms “substantially,” “approximately,” and “about”mean±10%, and in some embodiments, ±5%. The term “consists essentiallyof” means excluding other materials that contribute to function, unlessotherwise defined herein. Nonetheless, such other materials may bepresent, collectively or individually, in trace amounts.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, like reference characters generally refer to the sameparts throughout the different views. Also, the drawings are notnecessarily to scale, emphasis instead generally being placed uponillustrating the principles of the invention. In the followingdescription, various embodiments of the present invention are describedwith reference to the following drawings, in which:

FIG. 1A is a cross-sectional view of a frame die in accordance withvarious embodiments of the invention;

FIG. 1B is a top view of the frame die of FIG. 1A;

FIG. 1C is a bottom view of the frame die of FIG. 1A;

FIGS. 1D-1Z are cross-sectional views of frame dies in accordance withvarious embodiments of the invention;

FIG. 1AA is a cross-sectional view of a frame die electrically coupledto conductive traces in accordance with various embodiments of theinvention;

FIG. 2A is a cross-sectional view of a frame die incorporating multiplelight-emitting elements in accordance with various embodiments of theinvention;

FIG. 2B is a cross-sectional view of a frame die incorporating multiplelight-emitting elements each within a dedicated frame element inaccordance with various embodiments of the invention;

FIG. 2C is a plan view of the frame die of FIG. 2B;

FIGS. 3A, 3B, and 4A-4K are cross-sectional views of frame dies inaccordance with various embodiments of the invention;

FIGS. 5A and 5B are plan views of frame dies in accordance with variousembodiments of the invention;

FIG. 6 is a flow chart of a process for forming a frame die inaccordance with various embodiments of the invention;

FIGS. 7A-7G are cross-sectional views of various steps utilized tofabricate frame dies in accordance with various embodiments of theinvention;

FIG. 7H is a cross-sectional view of a step utilized within an alternateprocess of fabricating frame dies in accordance with various embodimentsof the invention;

FIGS. 7I-7L are cross-sectional views of steps for the fabrication offrame dies utilizing mold covers in accordance with various embodimentsof the invention;

FIGS. 7M-7O are cross-sectional views of steps utilized to fabricateframe dies incorporating multiple phosphor layers in accordance withvarious embodiments of the invention;

FIGS. 7P-7R are cross-sectional views of steps utilized to fabricateframe dies incorporating multiple phosphor layers in accordance withvarious embodiments of the invention;

FIG. 8A is a cross-sectional view of the frame wafer of FIG. 8B;

FIG. 8B is a plan view of a frame wafer in accordance with variousembodiments of the invention;

FIG. 8C is a plan view of a frame wafer in accordance with variousembodiments of the invention;

FIG. 9 is a flow chart of a process for determining the size ofthrough-holes of a frame wafer in accordance with various embodiments ofthe invention;

FIG. 10 is a flow chart of a process for forming a frame wafer inaccordance with various embodiments of the invention;

FIGS. 11A-11C are cross-sectional views of steps for the fabrication ofa frame wafer in accordance with various embodiments of the invention;

FIG. 11D is a cross-sectional view of a frame wafer in accordance withvarious embodiments of the invention;

FIG. 11E is a plan view of the frame wafer of FIG. 11D;

FIGS. 12A-12D are cross-sectional views of steps for the singulation oflight-emitting elements for the fabrication of frame dies in accordancewith various embodiments of the invention;

FIG. 13A is a cross-sectional view of light-emitting elements disposedon a base or tape in accordance with various embodiments of theinvention;

FIGS. 13B-13I are cross-sectional views of frame dies in accordance withvarious embodiments of the invention;

FIGS. 14A and 14B are graphs of reflectance as a function of wavelengthfor reflective coatings in accordance with various embodiments of theinvention;

FIG. 15 is a schematic CIE chromaticity diagram in accordance withvarious embodiments of the invention;

FIG. 16A is a graph of the effect of facet angle on light output powerfor frame dies with different reflecting surfaces in accordance withvarious embodiments of the invention;

FIG. 16B is a graph of the maximum divergence of color uniformity interms of the radially averaged Δu′v′ deviation from the spatiallyweighted average chromaticity over a view angle of about 0° to about 70°for the structures investigated in FIG. 16A;

FIG. 16C is a graph of the spatial non-uniformity of chromaticity(Δu′v′) as a function of polar angle for one azimuthal angle for a framedie in accordance with various embodiments of the invention;

FIG. 17A is a graph of the effect of facet angle on light output powerfor frame dies with different reflecting surfaces in accordance withvarious embodiments of the invention;

FIG. 17B is a graph of the maximum divergence of color uniformity interms of the radially averaged Δu′v′ deviation from the spatiallyweighted average chromaticity over a view angle of about 0° to about 70°for the structures investigated in FIG. 17A;

FIG. 18A is a graph of the effect of frame die height on light outputpower for frame dies with different facet angles in accordance withvarious embodiments of the invention;

FIG. 18B is a graph of the maximum divergence of color uniformity interms of the radially averaged Δu′v′ deviation from the spatiallyweighted average chromaticity over a view angle of about 0° to about 70°for the structures investigated in FIG. 18A;

FIG. 19A is a graph of the effect of facet angle on light output powerfor frame dies with different phosphor cap thicknesses in accordancewith various embodiments of the invention;

FIG. 19B is a graph of the maximum divergence of color uniformity interms of the radially averaged Δu′v′ deviation from the spatiallyweighted average chromaticity over a view angle of about 0° to about 70°for the structures investigated in FIG. 19A;

FIG. 20A is a graph of the effect of frame height on light output powerfor frame dies with different phosphor cap thicknesses in accordancewith various embodiments of the invention;

FIG. 20B is a graph of the maximum divergence of color uniformity interms of the radially averaged Δu′v′ deviation from the spatiallyweighted average chromaticity over a view angle of about 0° to about 70°for the structures investigated in FIG. 20A;

FIG. 21A is a graph of the effect of geometric scaling factor on lightoutput power for frame dies in accordance with various embodiments ofthe invention;

FIG. 21B is a graph of the maximum divergence of color uniformity interms of the radially averaged Δu′v′ deviation from the spatiallyweighted average chromaticity over a view angle of about 0° to about 70°for the structures investigated in FIG. 21A;

FIG. 21C is a graph of the effect of geometric scaling factor on lightoutput power for frame dies in accordance with various embodiments ofthe invention;

FIG. 21D is a graph of the maximum divergence of color uniformity interms of the radially averaged Δu′v′ deviation from the spatiallyweighted average chromaticity over a view angle of about 0° to about 70°for the structures investigated in FIG. 21C;

FIG. 22 is a graph of light output power for a large number of differentframe die geometries in accordance with various embodiments of theinvention;

FIGS. 23A-23C are histograms of the spectral distribution of light froma series of frame dies having three different frame heights inaccordance with various embodiments of the invention;

FIG. 24A is a graph of the average value of the angle of incidence oflight emitted by the light-emitting element of a phosphor-containingframe die as a function of frame height in accordance with variousembodiments of the invention;

FIG. 24B is a graph of the average value of the angle of incidence oflight emitted by the phosphor of a phosphor-containing frame die as afunction of frame height in accordance with various embodiments of theinvention;

FIG. 25A is a schematic diagram of a frame die having a light-emittingelement coupled to another component in accordance with variousembodiments of the invention;

FIG. 25B is an electrical schematic of a frame die having alight-emitting element coupled to a Zener diode in accordance withvarious embodiments of the invention;

FIG. 25C is a cross-sectional view of a frame die having the electricalschematic of FIG. 25B in accordance with various embodiments of theinvention;

FIGS. 26A and 26B are bottom views of a frame die incorporating anadditional electronic component in accordance with various embodimentsof the invention;

FIG. 27 is a cross-sectional view of a lighting device featuringmultiple frame dies in accordance with various embodiments of theinvention;

FIG. 28A is a cross-sectional view of a frame die with a co-moldedoptical fiber in accordance with various embodiments of the invention;

FIG. 28B is a cross-sectional view of a frame die incorporating an opticin accordance with various embodiments of the invention;

FIG. 28C is a cross-sectional view of a frame die incorporating anoptical element in accordance with various embodiments of the invention;

FIG. 28D is a cross-sectional view of an optic integrated with multipleframe dies in accordance with various embodiments of the invention;

FIG. 28E is a cross-sectional view of an optic that may be utilized withframe dies in accordance with various embodiments of the invention;

FIG. 28F is a cross-sectional view of a lighting device featuring aframe die at least partially inserted into a depression in an optic inaccordance with various embodiments of the invention;

FIGS. 29A and 29B are cross-sectional views of frame dies incorporatinglight-absorbing elements in accordance with various embodiments of theinvention;

FIG. 29C is a cross-sectional view of a frame die incorporating multiplelight-absorbing elements in accordance with various embodiments of theinvention;

FIG. 29D is a cross-sectional view of a frame die incorporating anelectronic die and a light-emitting or light-absorbing element inaccordance with various embodiments of the invention;

FIGS. 30A and 30B are cross-sectional views of frame dies incorporatingglass and/or substantially transparent frames in accordance with variousembodiments of the invention;

FIGS. 31A-31E are cross-sectional views of frame dies in accordance withvarious embodiments of the invention;

FIGS. 31F and 31G are plan views of frame dies in accordance withvarious embodiments of the invention; and

FIGS. 31H and 31I are cross-sectional views of frame dies in accordancewith various embodiments of the invention.

DETAILED DESCRIPTION

Embodiments of the present invention provide a new approach tointegration of phosphor and light-emitting elements, such as LED dies,that addresses a number of the deficiencies and difficulties present inthe current manufacture of phosphor-converted LEDs. Embodiments of thepresent invention provide novel structures and techniques for producingsuch devices to achieve relatively high efficiency and relatively lowcost. Advantageously, the phosphor may be integrated with alight-emitting element (LEE) (e.g., a light-emitting die) before it ismounted on a circuit board or placed into an intermediate-level package,for example as described in the '864 application and in the '543application.

FIG. 1A shows a cross-sectional schematic of one exemplary embodiment ofthe present invention. Structure 200, also referred to herein as a framedie, includes one or more LEEs 210, each of which features at least onecontact 220. As shown, LEE 210 is partially surrounded by a phosphor230, which is in turn supported by and optionally partially surroundedby a support structure (or “frame”) 270. At least a portion of eachcontact 220 is typically not covered by phosphor 230. In theconfiguration shown in FIG. 1A, LEE 210 features two contacts 220 thatare situated on the same face or side 214 of LEE 210. As shown, each ofthe contacts 220 preferably has a free terminal end that is not coveredby the phosphor 230 and that is available for electrical connection.Herein, “available for electrical connection” means the contact hassufficient free area to permit attachment to, e.g., a conductive trace,a circuit board, etc., and “free” means lacking any electricalconnection (and in preferred embodiments, any mechanical connection)thereto. In some embodiments of the present invention, phosphor 230 ispartially bounded by frame 270, which in some embodiments includes areflecting face 272 that is reflective to a wavelength of light emittedby LEE 210, phosphor 230, or both. A key aspect of various embodimentsof the invention is that frame 270 surrounds LEE 210 but permits accessto contacts 220 for attachment, for example to a circuit board orintermediate package, thus eliminating the need for a second die-attachstep internal to frame die 200. Frame 270 advantageously provides arelatively highly reflecting surface 272 to achieve high luminousefficacy, structural support for phosphor 230, and access to contacts220, resulting in package that provides high efficiency with arelatively low cost of materials and manufacture.

In some embodiments, a surface 260 of phosphor 230 is parallel orsubstantially parallel to a surface 217 of LEE 210. In some embodiments,surface 260 of phosphor 230 is parallel or substantially parallel tosurface 214 and/or surface 217 of LEE 210. A thickness 254 of phosphor230 over LEE 210 is shown in FIG. 1A as the same or substantially thesame over the entirety of LEE 210; however, this is not a limitation ofthe present invention, and in other embodiments thickness 254 ofphosphor 230 over LEE 210 varies. FIG. 1A shows surface 260 of phosphor230 as flat or substantially flat; however, this is not a limitation ofthe present invention, and in other embodiments surface 260 is curved,roughened, patterned, or textured in a regular, periodic, or randompattern. In some embodiments, phosphor 230 has, at least in part, asmooth, substantially continuous shape. In some embodiments, shapingand/or patterning or texturing of surface 260 is achieved during theformation or molding process, while in other embodiments shaping and/orpatterning or texturing is performed after the phosphor is molded orafter it is cured or partially cured. (As discussed herein, “phosphor”may refer to a binder or matrix material alone or a mixture of thebinder and wavelength-conversion material.)

FIG. 1B shows a view of the top of the structure shown in FIG. 1A, andFIG. 1C shows a view of the bottom of the structure shown in FIG. 1A.LEE 210 in FIG. 1B is shown as having a square cross-sectional shape;however, this is not a limitation of the present invention, and in otherembodiments LEE 210 is rectangular, hexagonal, circular, triangular, orhas any arbitrary shape and/or may have sidewalls forming any angle withrespect to surface 214 of LEE 210. In some embodiments, LEE 210 may havea rectangular shape, with one side having a length 212 and theorthogonal side having a length 212′. In some embodiments, LEE 210 mayhave a square shape, in which case length 212 is the same as orsubstantially the same as length 212′.

LEE 210 may be spaced apart from the edge of frame 270 by a gap 242. Insome embodiments, it is desirable to minimize gap 242 in order to reducethe amount of light emitted out the back of frame die 200 and to achievehigh efficiency; in such embodiments, gap 242 may have a value less thanabout 150 μm, less than about 100 μm, less than 50 μm, less than 25 μm,less than 10 μm, or even less than 5 μm. In some embodiments, gap 242 isthe same or substantially the same on all sides of LEE 210; however,this is not a limitation of the present invention, and in otherembodiments gap 242 may be different along different portions of LEE210. In other embodiments, discussed herein, additional features may beincorporated into frame die 200 to reduce light loss out the back offrame die 200, and in such embodiments reducing the extent of gap 242may have relatively less impact on efficiency.

In some embodiments, frame 270 has a height 252 that is greater than aheight 219 of LEE 210, as shown in FIG. 1A, resulting in a thickness 254of phosphor over LEE 210. In other embodiments, frame 270 may have aheight 252 that is less than height 219 of LEE 210 or a height 252 thatis substantially the same as LEE 210 height 219. In the embodiment shownin FIG. 1A, the top surface 260 of phosphor 230 is at the same orsubstantially the same as the top of frame 270; however, this is not alimitation of the present invention, and in other embodiments phosphor230 may extend beyond the top of frame 270, for example as shown in FIG.1D, or may be recessed below the top of frame 270. In FIG. 1D, the topsurface of phosphor 230 extends a distance 232 above frame 270. In someembodiments, frame 270 has a height 252 in the range of about 1 μm toabout 3000 μm, or in the range of about 25 μm to about 500 μm; however,the height of frame 270 is not a limitation of the present invention. Insome embodiments, a height 232 of phosphor 230 extending over frame 270may be less than about 3 mm, less than about 1 mm, less than about 0.5mm, less than about 0.25 mm, or less than about 0.1 mm. While FIG. 1Dshows phosphor 230 has having the same or substantially the samethickness within distance 232 above frame 270, this is not a limitationof the present invention, and in other embodiments the thickness withindistance 232 may vary above LEE 210 and frame 270.

In some embodiments of the present invention, the value of framedimension (or “frame width”) 244 may be in the range of about 25 μm toabout 5 mm; however, as will be discussed, other embodiments may havedifferent dimensions 244. In some embodiments of the present invention,LEE 210 has a height 219 in the range of about 1 μm to about 1000 μm. Insome embodiments, all or a portion of the substrate of LEE 210 may beremoved, and LEE 210 may have a height 219 in the range of about 1 μm toabout 25 μm. In some embodiments, the height 254 of phosphor 230 aboveLEE 210 is in the range of about 25 μm to about 1000 μm. The ranges forvarious dimensions given herein are for certain embodiments and as willbe understood, other dimensions may be employed for differentconfigurations, as described herein.

In some embodiments, the cross-sectional profile of frame 270 may besquare or rectangular, i.e., in some embodiments dimension 244 or framewidth 262 may be the same or substantially the same as height 252, whilein other embodiments dimension 244 and/or frame width 262 may be greaterthan height 252, and in yet other embodiments dimension 244 and/or framewidth 262 may be less than height 252. In some embodiments, surface 272forms an angle 279 with the base of frame 270.

Frame 270 typically has a top opening and a bottom opening, for examplea top opening and a bottom opening of the aperture that extends throughthe frame. In some embodiments, the top and bottom openings may have thesame or substantially the same shape. In some embodiments, as shown inFIGS. 1A-1C, the top opening is rectangular having a width and a lengthof 267 and 267′ respectively, and the bottom opening is rectangular andhas a width and a length of 265 and 265′ respectively. In someembodiments, top opening width 267 and length 267′ may essentially thesame as frame width 262 and length 262′ as shown in FIG. 1B, while inother embodiments the top opening width may be different from the framewidth, for example as shown in FIG. 1E. In some embodiments, the topopening is square, in which case dimensions 267 and 267′ are the same orsubstantially the same. In some embodiments, the bottom opening issquare, in which case dimensions 265 and 265′ are the same orsubstantially the same. In some embodiments, the top opening and thebottom opening have substantially the same shape (but with the topopening being larger than the bottom opening), with dimensions 267,267′, 265, and 265′ scaled appropriately.

In some embodiments, dimensions 265 and/or 265′ may be in the range ofabout 0.15 mm to about 5 mm; however, this is not a limitation of thepresent invention, and in other embodiments these dimensions may bedifferent. In some embodiments, dimensions 262 and/or 262′ may be in therange of about 0.25 mm to about 5 mm; however, this is not a limitationof the present invention, and in other embodiments, for example as shownin FIGS. 2A-2C, where frame die 200 includes multiple sub-frames, thelateral dimension of frame 270 may be larger.

In the embodiments shown in FIGS. 1A and 1D, reflecting surface 272 isshown as a flat surface; however, this is not a limitation of thepresent invention, and in other embodiments reflecting surface 272 offrame 270 may have other profiles or shapes. For example, frame 270 mayinclude more than one non-parallel surface, e.g., reflecting surface 272may include or consist essentially of two or more non-parallel surfaces274 and 276, as shown in FIG. 1E. In the example shown in FIG. 1E,surface 276 extends the lateral dimension of frame 270 (shown as 244 inFIG. 1A) by an extension length 245 as shown in FIG. 1E, and phosphor230 extends above the frame, forming a phosphor cap 277. Frame width 262and length 262′ and dimension 244 include the extension length 245, whenapplicable. In various embodiments, frame width 262 and length 262′ maybe in the range of about 0.25 mm to about 10 mm. While FIG. 1E showssurface 276 as parallel or substantially parallel to surface 240, thisis not a limitation of the present invention, and in other embodimentssurface 276 is not parallel to surface 240. (As shown in FIG. 1A, the“top surface” of the frame 270 may simply be the apex formed by theintersection of the sidewall of the aperture and the exterior lateralsurface of frame 270, i.e., a substantially linear “surface” with littlelateral extent. In other embodiments, as shown in FIG. 1E, the topsurface of the frame 270 may have a distinct lateral extent surroundingthe aperture.) FIGS. 1F and 1G show other examples of embodiments offrame die 200, in which reflecting surface 272 of frame 270 is curved.In other embodiments, reflecting surface 272 may include flat surfaces,curved surfaces, combinations of flat and curved surfaces, or anyarbitrary shape.

While face 260 of phosphor 230 is shown as a flat planar surface inFIGS. 1A and 1D-1G, this is not a limitation of the present invention,and in other embodiments face 260 may include multiple flat surfaces,for example surfaces 260 and 260′ as shown in FIG. 1J, a curved surfaceas shown in FIG. 1H, combinations of flat and curved surfaces 260′ and260 respectively, as shown in FIG. 1I, or any arbitrary shape. Whileface 260 of phosphor 230 is shown as symmetric with respect to LEE 210in FIGS. 1A and 1D-1J, this is not a limitation of the presentinvention, and in other embodiments face 260 may include or consistessentially of multiple faces that are not symmetric with respect to LEE210, for example as shown in FIG. 1K.

While sidewall 250 of frame 270 is shown in FIG. 1A as being flat andsubstantially perpendicular to face 240 of frame 270, this is not alimitation of the present invention, and in other embodiments sidewall250 may include or consist essentially of multiple flat surfaces, acurved surface, multiple curved surfaces, combinations of curved andflat surfaces or any arbitrary shape, for example as shown in FIG. 1L.

While surface 272 is shown in FIG. 1A as being flat, this is not alimitation of the present invention. FIG. 1L shows an embodiment of thepresent invention in which surface 272 is curved. FIG. 1M shows anembodiment of the present invention in which surface 274 of frame 270 issubstantially perpendicular to surface 276 of frame 270. While FIG. 1Mshows phosphor 230 having a curved shape, this is not a limitation ofthe present invention, and in other embodiments phosphor 230 may havedifferent shapes.

FIG. 1N shows an embodiment of the present invention in which frame 270has a height less than the height of LEE 210. The embodiment in FIG. 1Ndepicts a flat top of phosphor 230; however, this is not a limitation ofthe present invention, and in other embodiments phosphor 230 may have adifferent shape.

FIG. 1O shows an embodiment of the present invention in which at least aportion of surface 260 of phosphor 230 is below the top of frame 270(i.e., the height of at least a portion of the phosphor is less than theheight of at least a portion of the frame). FIG. 1P shows an embodimentin which there is a thin portion of phosphor, identified as a web 231,extending over a portion of frame 270. While FIG. 1P shows web 231 overall or substantially all of surface 276, this is not a limitation of thepresent invention, and in other embodiments web 231 may cover only oneor more portions of surface 276 and/or may cover one or more portions ofsurface 274 and/or LEE 210. FIG. 1Q shows an embodiment in whichphosphor 230 includes or consists essentially of a substantiallyconformal coating around LEE 210, which is in turn surrounded by aphosphor 238. In some embodiments, phosphor 230 contains one or morewavelength-conversion materials and phosphor 238 does not containwavelength-conversion material, while in other embodiments phosphor 238contains one or more wavelength-conversion materials and phosphor 230does not contain wavelength-conversion material. In some embodiments,the conformal coating may have a thickness in the range of about 25 μmto about 400 μm; however, the thickness of the conformal coating is nota limitation of the present invention.

In some embodiments of the present invention, surface 272 includes orconsists essentially of more than one distinct surface or facet. FIG. 1Rshows an example of one embodiment in which surface 272 includes orconsists essentially of two distinct portions 272 and 272′. While FIG.1R shows two distinct portions of surface 272, this is not a limitationof the present invention, and in other embodiments surface 272 mayinclude or consist essentially of any number of distinct portions. WhileFIG. 1R shows each of the two distinct portions of surface 272 beingstraight, this is not a limitation of the present invention, and inother embodiments surface 272 may include or consist essentially of anynumber of distinct portions, each of which may be straight, curved, orhave any arbitrary shape. While FIG. 1R and FIG. 1Q show surface 272shaped internally, i.e., facing LEE 210 and/or concave, this is not alimitation of the present invention, and in other embodiments an upperportion of the frame may be shaped, as shown in FIG. 1S. As discussedwith respect to FIG. 1R, surface 296 in FIG. 1S may include or consistessentially of one or more portions, each of which may have any shape.

In some embodiments of the present invention, the surface 272 may beused advantageously to adjust one or more optical characteristics offrame die 200, for example angular color uniformity or lightdistribution pattern. For example, a frame die similar to that shown inFIG. 1R may be used to produce a relatively more collimated light outputdistribution than that of the frame die depicted in FIG. 1A.

In some embodiments of the present invention, surface 272 may include orconsist essentially of random or systematically designed or engineeredpatterns or structures. For example, FIG. 1T shows an embodiment of thepresent invention in which surface 272 includes or consists essentiallyof a number of ridges or steps. While FIG. 1T shows surface 272including or consisting essentially of a number of regular steps orridges, each having the same or substantially the same size and spacing,this is not a limitation of the present invention, and in otherembodiments surface 272 may include or consist essentially of steps orridges having different sizes and/or spacing. Such patterns andstructures may be engineered to improve the frame die performance, forexample uniformity of the light intensity distribution, or coloruniformity, for example angular color uniformity; however, this is not alimitation of the present invention, and in other embodiments suchpatterns and/or structures may be utilized to affect and/or controlother properties, for example luminous flux, correlated colortemperature (CCT), or the like.

In some embodiments of the present invention, one or more materials 278may be formed on or over surface 272, for example as shown in FIG. 1U.Material 278 may be the same as or different from the material of frame270. Material 278 may be in the form of particles, for example as shownin FIG. 1U; however, this is not a limitation of the present invention,and in other embodiments material 278 may have other forms. For example,material 278 may include or consist of one or more layers, or may be inthe form of microparticles, nanoparticles, or may have a combination offorms. Material 278 may impart advantageous optical, mechanical, and/orchemical properties to frame die 200, for example to modify thereflectance of one or more surfaces of the frame die 200. For example,in some embodiments of the present invention, material 278 may includeor consist essentially of one or more dielectric layers, for examplesilicon oxide, silicon nitride, or the like. In some embodiments of thepresent invention, material 278 may include or consist essentially ofone or more metal layers, for example aluminum, silver, gold, chromium,titanium, or the like. In some embodiments of the present invention,material 278 may include or consist essentially of one or more layers,for example including one or more dielectric and/or metallic layers. Thespecific structure of material 278 is not a limitation of the presentinvention. In some embodiments of the present invention, one or morelayers of material 278 may form a reflecting surface, for example aBragg reflector. In some embodiments of the present invention, thereflecting surface may be a specular or diffuse reflecting surface. Insome embodiments of the present invention, the reflectance of material278 may be engineered to have a different reflectance as a function ofincident wavelength and/or angle of incidence or position along surface272. In some embodiments, material 278, by itself or in combination withother geometrical and/or optical characteristics of other elements offrame die 200, for example angle 279, frame height 252, frame dimension244, thickness 254 of phosphor 230 over LEE 210, or the like, may beengineered to produce specific optical characteristics of frame die 200,for example a specific light distribution pattern, an improved angularcolor uniformity, a specific CCT, or the like. In some embodiments ofthe present invention, material 278 may include or consist essentiallyof silicon oxide, aluminum, silver, chromium, gold, titanium oxide, orcombinations of these materials. In some embodiments of the presentinvention, material 278 may cover all of surface 272, while in otherembodiments material 278 may cover one or more portions of surface 272.In some embodiments, material 278 may cover all or one or more portionsof surface 276 and/or surface 250 and/or surface 240. For example, insome embodiments of the present invention material 278 may be formedover all or one or more portions of the surface of frame 270.

Frame die 200 is shown in FIG. 1A as having no phosphor 230 coveringface 250 of frame 270; however, this is not a limitation of the presentinvention, and in other embodiments phosphor 230 may cover all or one ormore portions of face 250. For example, FIG. 1V shows phosphor 230covering faces 250 of frame 270. While FIG. 1V shows phosphor 230covering all or substantially all of faces 250, this is not a limitationof the present invention, and in other embodiments phosphor 230 may onlycover one or more portions of one or more faces 250. While FIG. 1V showsphosphor 230 extending above frame 270, this is not a limitation of thepresent invention, and in other embodiments phosphor 230 may not extendabove frame 270. For example, in some embodiments of the presentinvention, phosphor 230 formed over all or portions of face 250 may notbe contiguous with phosphor 230 formed over LEE 210. An example of thisis shown in FIG. 1W, in which phosphor 230 is not continuous with aphosphor 230′. In some embodiments of the present invention, phosphor230 formed over all or a portion of face 250 may be the same as phosphorformed over LEE 210; however, this is not a limitation of the presentinvention, and in other embodiments phosphor 230 formed over all or aportion of face 250 may be different from phosphor 230 formed over LEE210.

In some embodiments of the present invention, phosphor 230 may notextend to the edge of frame 270. For example, in some embodiments of thepresent invention, phosphor 230 may be formed over only a portion ofsurface 276. For example, in some embodiments, phosphor 230 may notextend to the outer edge of surface 276, for example as shown in FIG.1X.

FIGS. 1A-1X show examples of frame die 200 having a symmetric frame 270;however, this is not a limitation of the present invention, and in otherembodiments frame 270 may be asymmetric. For example, frame 270 may havedifferent heights 252, different frame dimensions 244, different angles279, different phosphor heights 254 over LEE 210, or the like indifferent portions of frame die 200. For example, FIG. 1Y shows anembodiment of the present invention in which frame 270 has differentangles 279 and 279′ in different portions of frame 270, for example onopposite sides of frame 270. In some embodiments of the presentinvention, other aspects of frame die 200 may be asymmetric, for examplethe phosphor, for example as shown in FIG. 1K, position of LEE 210within frame 270, length of frame dimension 244, gap 242, or the like.

In some embodiments of the present invention, asymmetry may not belimited to dimensions. For example, material or layer characteristicsmay also be asymmetric or non-uniform. For example, surfaces 272 and/or276 may have different properties in different portions of frame die200, and/or may be composed of different materials, or films withdifferent thicknesses, different materials, or the like. Asymmetries inthe structure of frame die 200 may alter the optical characteristics andin some embodiments of the present invention be utilized to provideframe die 200 with specific optical performances such as light outputdistribution or angular color uniformity or the like. In someembodiments of the present invention, asymmetries in the structure offrame die 200 may be utilized to produce similar asymmetries in theoptical characteristics of frame die 200, for example an asymmetriclight distribution pattern, an asymmetric spectral characteristic orcolor temperature or the like.

In some embodiments of the present invention, frame 270 may beelectrically insulating, while in other embodiments frame 270 may beelectrically conductive. In some embodiments of the present invention,all or one or more portions of frame 270 may be covered or protected,for example with a dielectric or insulating material. For example, FIG.1Z shows material 275 covering all or substantially all of frame 270. Insome embodiments of the present invention, the material 275 may reduceor eliminate exposure of frame 270 to moisture or water vapor or otherpotentially harmful airborne or surface contaminants. In someembodiments of the present invention, all or one or more portions offrame 270 may be covered by an insulating layer. In some embodiments ofthe present invention, surface 240 may include or consist essentially ofone or more materials with specific electrical properties. For example,in some embodiments of the present invention, all or one or moreportions of surface 240 may be formed of or covered by a dielectricmaterial such as silicon oxide, silicon nitride, titanium oxide,aluminum oxide, or a polymer. For example, in some embodiments of thepresent invention, insulating layer 275 may be formed over all or one ormore portions of surface 240 and/or surface 250 or other portions offrame 270. In some embodiments of the present invention, an insulatingmaterial or layer between frame 270 and underlying conductive traces mayminimize or prevent the flow of electrical current from underlyingconductive traces through frame 270, resulting in a reduction orelimination in current flowing to LEE 210. FIG. 1AA shows an example oflayer 275 disposed over surface 240, with frame die 200 disposed overconductive traces 298, which are in turn disposed over substrate 297. Insome embodiments of the present invention, insulating layer 275 mayinclude or consist essentially of silicon oxide, silicon nitride,aluminum oxide, one or more polymers, or the like. In some embodimentsof the present invention, insulating layer 275 may include or consistessentially of more than one layer. In some embodiments of the presentinvention, insulating layer 275 may be formed by evaporation,sputtering, chemical vapor deposition, printing, spraying, conformalcoating, or the like. The method of formation of insulating layer 275 isnot a limitation of the present invention. In some embodiments of thepresent invention, insulating layer 275 may have a thickness in therange of about 20 nm to about 10 μm, or in the range of about 100 nm toabout 4 μm.

FIGS. 1A-1AA show frame die 200 as including one LEE 210; however, thisis not a limitation of the present invention, and in other embodimentsframe die 200 includes more than one LEE 210. FIG. 2A shows an exampleof an embodiment having three LEEs 210 that are all included in oneframe element 270. While FIG. 2A shows three LEEs 210 in frame die 200,this is not a limitation of the present invention, and in otherembodiments frame die 200 may have fewer or more LEEs 210.

FIG. 2B shows an example of an embodiment of the present inventionhaving three LEEs 210′, 210″, and 210′″, each of which is in its ownsub-frame element 270′, 270″, and 270′″, respectively. FIG. 2C shows aplan view of the structure of FIG. 2B; FIG. 2B is a cross-sectional viewof the structure shown in FIG. 2C, along cut line 299-299′. Thestructure shown in FIG. 2C includes a 3×3 array of sub-frames; however,this is not a limitation of the present invention, and in otherembodiments the array of sub-frames may have more or fewer sub-frames.The structure shown in FIG. 2C has a square array of sub-frames;however, this is not a limitation of the present invention, and in otherembodiments the array of sub-frames may have different shapes, forexample a linear array (a line of sub-frames), rectangular, or anyarbitrary shape. Similar to the structure shown in FIG. 2C, LEEs 210within the structure shown in FIG. 2A may be formed in a linear array, asquare array, a rectangular array, or any arbitrary positioning ofmultiple LEEs 210.

In some embodiments of the present invention, multiple LEEs 210 of asingle frame die 200 are all the same, while in other embodiments theyare made up of at least two different types of LEEs 210. In someembodiments of the present invention, different types of LEEs 210 emitat different wavelengths. For example, frame die 200 may include one ormore of each of three different types of LEEs 210, where at least onetype emits in the blue wavelength range, at least one in the greenwavelength range and at least one in the red wavelength range. In oneembodiment, frame die 200 may include one or more of each of twodifferent types of LEEs 210, where at least one type emits in the bluewavelength range and at least one in the red wavelength range. Thespecific configurations of the LEEs 210 in frame die 200, as well astheir operating characteristics and properties, are not limitations ofthe present invention. In one embodiment of the present invention,different types of LEEs 210 have different light output powers. In oneembodiment, phosphor 230 may be composed of multiple portions orvolumes, where each portion or volume includes or consists essentiallyof one or more phosphors different from one or more phosphors in anotherportion. In one embodiment of this example, one or more portions includeor consist essentially of only a transparent binder material, while oneor more other portions include or consist essentially of a binder andone or more phosphors.

In some embodiments of the present invention, frame die 200 may emitmore than one color of light, for example frame die 200 may have two ormore volumes of different phosphors 230, which when excited by LEE 210may emit light of two different colors. In some embodiments, frame die200 may include two or more LEEs 210, and optionally two or more volumesof different phosphors 230, which may be separately stimulated (each byone or more LEES 210) to produce light of different colors.

In some embodiments of the present invention, reflecting surface 272 mayinclude or consist essentially of one or more layers, for example ametallic layer such as gold, silver, aluminum, chromium, titanium, orthe like. In some embodiments, reflecting surface 272 may include orconsist essentially of one or more dielectric layers, for example adielectric mirror or Bragg reflector. Dielectric layers may include orconsist essentially of one or more of silicon dioxide, titanium oxide,silicon nitride, zinc oxide or other dielectric materials. In someembodiments, reflecting surface 272 may include or consist essentiallyof a combination of metallic layers and dielectric layers. In someembodiments, reflecting surface 272 may be the surface of frame 270, forexample when frame 270 is formed of a reflective material, for example awhite polymer or plastic material. In various embodiments, reflectingsurface 272 has a reflectivity to a wavelength of light emitted by LEE210 and/or phosphor 230 of at least 80%, at least 90%, at least 95%, orat least 98%.

FIG. 3A shows an embodiment of the present invention similar to that ofFIG. 1A, but including a contact layer 310. In some embodiments, contactlayer 310 covers all or a portion of LEE contact 220 and all or aportion of surface 240 of frame 270. In some embodiments, contact layer310 is electrically coupled to contact 220 and provides a contact regionlarger than that of contact 220 for subsequent attachment of frame die200 to, e.g., one or more conductive traces. In some embodiments,contact layer 310 includes or consists essentially of one or moreelectrically conductive layers, for example chromium, titanium, gold,silver, aluminum, nickel, or the like. Contact layer 310 may be formedusing a variety of different techniques, for example evaporation,sputtering, plating, chemical vapor deposition, lamination, or the like.The specific materials and means of formation of contact layer 310 arenot limitations of the present invention. In some embodiments of thepresent invention, contact layer 310 may have a thickness in the rangeof about 10 nm to about 50 μm. In some embodiments, contact layer 310may have a thickness in the range of about 100 nm to about 5 μm. In someembodiments, contact layer 310 may have a thickness in the range ofabout 20 μm to about 40 μm.

In some embodiments, contact layer 310 is reflective to a wavelength oflight emitted by LEE 210 and/or phosphor 230. As shown in FIG. 3A,contact layer 310 covers all or a portion of gap 242, and may, inembodiments where contact layer 310 is reflective to a wavelength oflight emitted by LEE 210 and/or phosphor 230, reduce or substantiallyeliminate light loss through gap 242 between LEE 210 and frame 270. Insome embodiments, contact layer 310 has a reflectivity greater thanabout 50%, greater than about 75%, or greater than about 90% to awavelength of light emitted by LEE 210 and/or phosphor 230. In someembodiments, contact layer 310 may be both electrically conductive andreflective. In some embodiments, contact layer 310 may include orconsist essentially of more than one layer to achieve electricalconductivity and optical reflectivity. In some embodiments, contactlayer 310 may be used to interconnect one or more LEEs of structuresshown in FIGS. 2A-2C having multiple LEEs 210, such that the frame die200 has only two contacts, for example as shown in FIG. 3B. FIG. 3Bshows multiple contact layers 310 electrically interconnecting LEEs 210.LEEs 210 may be electrically connected in series, parallel, or anyfashion. FIG. 3B shows two optional elements, a contact 320 and aninsulating layer 330. Insulating layer 330 may be used to cover all or aportion of contact layer 310 and/or all or a portion of the bottom offrame die 200. Insulating layer 330 may be used to prevent undesiredelectrical coupling between contacts 220 on LEE 210 and underlyinglayers or materials, for example when attached to a package or circuitboard. Contact 320 is an additional contact layer that is electricallyconductive and electrically coupled to one or more contact layers 310and/or one or more contacts 220. Contact 320 may provide a larger padarea for subsequent contact to a package or circuit board, for examplemaking mounting easier or providing for a reduced contact resistance. Invarious embodiments, contact structures such as those including contactlayer 310, insulating layer 330, and contact 320 may be used tointerconnect multiple LEEs 210 and to permit a smaller number ofcontacts to a single frame die 200 that incorporates multiple LEEs 210.

FIG. 4A shows another embodiment of the present invention that featuresa transparent material 410 between phosphor 230 and LEE 210. In someembodiments, transparent material 410 surrounds LEE 210 and fills orpartially fills the interior region of frame 270. In such embodiments,phosphor 230 is spaced apart from LEE 210 by material 410. In someembodiments, this separation reduces heating of phosphor 230 and thusmay result in an increased phosphor efficiency. In some embodiments,phosphor 230 may be formed separately from the process of formation ofportion 420 of the structure (FIG. 4A). For example, this may simplifythe manufacture and/or permit increased control and uniformity in theformation of phosphor 230, resulting in improved uniformity of opticalcharacteristics, for example color temperature, CRI, and the like. Whilethe structure in FIG. 4A has a flat slab of phosphor 230, this is not alimitation of the present invention, and in other embodiments phosphor230 may have different shapes, for example as shown in FIG. 4B and FIG.4C. In some embodiments, frame die 200 may be formed using onlytransparent material 410 (i.e., without any phosphor 230), for exampleas shown in FIG. 4D. In various embodiments, the structure of FIG. 4Dmay be used as a package for non-phosphor-converted light-emittingstructure. In the structure shown in FIG. 4A the interface betweenphosphor 230 and material 410 is shown as flat and substantiallyparallel to the top surface of LEE 210; however, this is not alimitation of the present invention, and in other embodiments theinterface between phosphor 230 and material 410 may be curved (as shownin FIG. 4E) or have other shapes. While FIG. 4E shows the top ofmaterial 410 as having a concave shape, this is not a limitation of thepresent invention, and in other embodiments material 410 may have aconvex top surface or may have any shape. In some embodiments, therelative positions of transparent material 410 and phosphor 230 may bemodified such that phosphor 230 surrounds LEE 210 and transparentmaterial 410 is disposed over at least a portion of phosphor 230. Insome embodiments, transparent material 410 may be substantially a slabform, while in other embodiments transparent material may be shaped, forexample have a hemispherical shape, a partial hemisphere shape, apyramid shape, or may be shaped to form an optic, for example arefractive optic or a Fresnel lens.

FIG. 4F shows a structure similar to that of FIG. 4A; however, in FIG.4F material 410 covers frame 270, such that phosphor 230 does notcontact frame 270 and is only in contact with material 410.

While FIGS. 4A-4F show embodiments of the present invention in whichphosphor 230 is formed within the lateral extent of frame 270, this isnot a limitation of the present invention, and in other embodimentsphosphor 230 may cover all or one or more portions of sidewall 250. Forexample, FIG. 4G shows a structure similar to the structure of FIG. 4A;however, in the structure of FIG. 4G phosphor 230 extends beyond thelateral edge of frame 270 and is disposed over sidewalls 250. In someembodiments of the present invention, phosphor 230 is uniformly disposedover sidewalls 250; however, this is not a limitation of the presentinvention, and in other embodiments phosphor 230 may have differentthickness or different concentration or different properties ondifferent portions of sidewalls 250. For example, in some embodiments ofthe present invention, phosphor 230 may be different on sidewall 250that it is on sidewall 250′.

In some embodiments of the present invention, transparent material 410may include or consist essentially of binder, for example silicone orepoxy. In some embodiments, phosphor 230 or transparent material 410 mayinclude additional materials or particles, for example material toscatter or diffuse light, e.g., fumed silica, fumed alumina, TiO₂, orthe like.

In the structure described in reference to FIG. 4A, transparent material410 is disposed over LEE 210 and phosphor 230 is disposed overtransparent material 410; however, this is not a limitation of thepresent invention, and in other embodiments phosphor 230 may be disposedover LEE 210 and transparent material 410 may be disposed over phosphor230. For example, FIG. 4H shows an embodiment of the present inventionin which phosphor 230 is disposed over LEE 210 and surface 272, andtransparent material 410 is disposed over phosphor 230.

In some embodiments of the present invention, transparent material 410may cover all or a portion of sidewalls 250. For example, FIG. 4I showsan embodiment of the present invention in which transparent material 410covers all or substantially all of sidewalls 250. In such embodiments,transparent material 410 covers all or substantially all of the portionof the sidewall 234 of phosphor 230 extending above the top of frame270; however, this is not a limitation of the present invention, and inother embodiments transparent material 410 may only cover sidewalls 250of frame 270, or may only cover portions of sidewalls 250 of frame 270.

In some embodiments of the present invention, transparent material 410may be disposed over phosphor 230 and all or one or more portions ofsidewalls 250. For example, FIG. 4J shows an embodiment of the presentinvention in which transparent material 410 is disposed over sidewalls250 and surface 260 of phosphor 230. While FIGS. 4H and 4I showtransparent material 410 having a substantially rectangular shape andsubstantially conforming to the underlying shape of frame 270 andphosphor 230, this is not a limitation of the present invention, and inother embodiments transparent material 410 may have a different shapefrom that of frame 270 and/or phosphor 230. For example, in someembodiments of the present invention transparent material may have ahemispherical shape, a parabolic shape, a triangular shape or anyarbitrary shape. FIG. 4K shows an example of one embodiment of thepresent invention in which transparent material 410 has a hemisphericalshape that is disposed over surface 260 of phosphor 230 and sidewalls250.

In some embodiments of the present invention, transparent material 410may protect frame die 200, for example, by encapsulating all orsubstantially all of phosphor 230. In some embodiments, transparentmaterial 410 may reduce or eliminate exposure of phosphor 230 and/orframe 270 to moisture or water vapor or other potentially harmfulairborne or surface contaminants. In some embodiments of the presentinvention, transparent material 410 may be utilized to modify theoptical and/or structural and mechanical characteristics of frame die200. For example, transparent material 410 may be engineered to providea specific light distribution pattern, a specific angular coloruniformity, and/or a specific CCT; however, the shape of transparentmaterial 410 is not a limitation for present invention, and material 410may be formed in any arbitrary shape.

In some embodiments of the present invention, the interior of frame 270is a square, as shown in FIG. 1A, or a rectangle; however, this is not alimitation of the present invention, and in other embodiments theinterior and/or the exterior shape of frame 270 may have othergeometries, for example octagonal as shown in FIG. 5A, or hexagonal, orany arbitrary shape. Differently shaped frames 270 may be used incombination with differently shaped LEEs 210, as shown for example inFIG. 5B.

In some embodiments of the present invention, frame die 200 is formedbefore attachment (electrical and/or mechanical) to a package orsubstrate. In some embodiments, frame die 200 may itself function as apackage, while in other embodiments frame die 200 may be incorporatedinto additional packaging components. In some embodiments of the presentinvention, frame die 200 may be attached directly to a circuit board,substrate or the like without intermediate packaging. A key element ofembodiments of the present invention is that frame die 200 does notincorporate a second level contact to LEE 210, as contacts 220 of LEE210 are the contacts for frame die 200.

FIG. 6 is a flow chart of a process 600 for forming a frame die 200.Process 600 is shown having eight steps; however, this is not alimitation of the present invention, and in other embodiments theinvention has more or fewer steps and/or the steps may be performed indifferent order. In step 610, a first surface or base is provided. Instep 620, one or more LEEs are placed or formed on the base. In step630, a frame wafer is provided. In step 640, the frame wafer is mated tothe base. In step 650, the phosphor is provided. In step 660, thephosphor is formed over the LEE and base, resulting in a composite framewafer. In step 670, the phosphor is cured. In step 680, the compositeframe wafer containing the phosphor-coated LEEs is separated orsingulated into frame dies 200. A step to remove the base (not shown inFIG. 6) may be implemented at different points in the process, asdiscussed herein. Various approaches to manufacturing and using framedies 200 are discussed below. The terms “frame wafer” and “compositeframe wafer” are used to identify elements of the structure duringmanufacture, before singulation step 680. In some embodiments of thepresent invention, singulation step 680 is optional. In someembodiments, step 620 may take place after step 640, i.e., the framewafer is provided (step 630) and mated to the base (step 640) and thenLEEs are placed on the base in the through-holes in the frame wafer(step 620).

FIGS. 7A-7F depict one embodiment of process 600. In this embodiment ofthe present invention, a base 710 is provided (step 610) and LEEs 210are placed on or adhered to base 710 (step 620) with contacts 220adjacent to base 710 (FIG. 7A). Base 710 may also be referred to as a“mold substrate.” In some embodiments of the present invention, base 710includes or consists essentially of an adhesive film or tape. In someembodiments, base 710 includes or consists essentially of a materialwhich has a relatively low adhesion to phosphor 230, that is, it permitsremoval of cured phosphor 230 from base 710. In some embodiments of thepresent invention, the base material deforms such that contacts 220 ofLEEs 210 penetrate below the surface of base 710, for example thecontacts 220 may be embedded into base 710. In some embodiments of thepresent invention, base 710 is the same as or similar to dicing ortransfer tapes used in the semiconductor industry for singulation and/ortransfer of dies, for example Revalpha from Nitto Denko Corporation ortapes from Semiconductor Equipment Corporation. In some embodiments ofthe present invention, base 710 includes or consists essentially of awater-soluble material or adhesive, or may be covered or be partiallycovered with a water-soluble material. For example, the adhesive of base710 or the liner or both may be water-soluble. In some embodiments ofthe present invention, the water-soluble material includes or consistsessentially of a water-soluble tape, for example 3M type 5414. In someembodiments of the present invention, base 710 includes or consistsessentially of a silicone or a silicone-based material, for example PDMSor GelPak material from the Gel-Pak Corporation.

In some embodiments of the present invention, base 710 includes orconsists essentially of a material with variable adhesive force. In suchembodiments, the adhesive force may be changed after formation andcuring of the phosphor, to make it easier to remove the frame die orframe die wafer from base 710. (A composite frame wafer is hereindefined as multiple semiconductor dies suspended in a binder andsurrounded by a frame. The frame may have multiple openings, and one ormore semiconductor dies suspended in a binder within each opening.) Insome embodiments of the present invention, such a variable adhesiveforce material may achieved using a thermal release tape or a UV releasetape. In some embodiments of the present invention, the variableadhesive force material may be achieved by using an electrostatic chuck(LEEs 210 are formed or placed on the electrostatic chuck, similar tothe structure shown in FIG. 7A). In such embodiments, LEEs 210 are heldin place on the electrostatic chuck by electrostatic forces that may beactivated or deactivated electrically.

In some embodiments of the present invention, it is desirable for all ora portion of the face of contact 220 to be exposed after formation offrame die 200, that is, to not be covered by phosphor 230. In someembodiments of the present invention, placing or adhering all or aportion of the face of contact 220 adjacent to base 710 preventscoverage or formation of phosphor 230 over all or a portion of contact220 or over all or a portion of the face of contact 220. In someembodiments of the present invention, the thickness, hardness and/orother properties of a coating on base 710, or the properties of base710, for example an adhesive thickness, chemical composition, surfaceenergy, hardness, elasticity, etc., may be varied to ensure the desiredlevel of exposure of contacts 220, for example by proximity to base 710or partial or full embedding of contacts 220 into base 710.

In some embodiments of the present invention, base 710 includes orconsists essentially of a surface or a mold (e.g., a non-flat surface).Base 710 may include or consist essentially of one or more of a varietyof materials, for example glass, PET, PEN, plastic film, tape, adhesiveon plastic film, metal, acrylic, polycarbonate, polymers, silicone,polytetrafluoroethylene (Teflon), or the like. In some embodiments, base710 is rigid or substantially rigid, while in others base 710 isflexible. In some embodiments of the present invention, it isadvantageous for base 710 to include or consist essentially of a“non-stick” material such as polytetrafluoroethylene, or a fluorinatedmaterial such as Fluon ETFE produced by Asahi Glass, or to include anon-stick coating over the surface or portion of the surface that maycome in contact with phosphor 230 (for example the binder in phosphor230) so that phosphor 230 does not stick to base 710. In someembodiments of the present invention, base 710 includes or consistsessentially of a layer of material that does not adhere well to thebinder material. In some embodiments of the present invention, base 710includes or consists essentially of a water-soluble material oradhesive, or base 710 is partially or completely lined with awater-soluble material to aid in the release of base 710 from thematerial formed in base 710. In some embodiments of the presentinvention, base 710 includes or consists essentially of or is partiallyor fully lined with a water-soluble tape, for example 3M type 5414. Insome embodiments, base 710 is transparent to light, for example tovisible, infrared, and/or UV radiation. In some embodiments of thepresent invention, the area of base 710 is in the range of about 0.25mm² to about 900 cm²; however, the area of base 710 is not a limitationof the present invention, and in other embodiments the area of base 710is smaller or larger to accommodate the size of the frame (provided instep 630 of process 600).

In some embodiments of the present invention, contacts 220 of LEEs 210have a thickness of between about 0.1 μm and about 5 μm. In otherembodiments, contacts 220 have a larger thickness, for example betweenabout 5 μm and about 50 μm. In some embodiments of the presentinvention, contacts 220 having a larger thickness may include or consistessentially of stud bumps. Larger contact thickness may be advantageousfor some embodiments in which it is desirable to ensure that the lightemitting region of the LEE is buried deeper within the phosphor.

A spacing 705 between adjacent LEEs 210 may be adjusted so that each LEE210 is surrounded by (and optionally centered or substantially centeredwithin the aperture) a portion of the frame wafer 720 (FIG. 7B) afterstep 640 of process 600. As will be discussed herein, spacing 705 may bemainly determined by the frame wafer dimensions.

The next step (step 630) in process 600 is to provide frame wafer 720 asshown in FIG. 7B. Frame wafer 720 includes or consists essentially ofone or more materials having at least one through-hole (or “aperture”)730. In some embodiments of the present invention, frame wafer 720 has alarge number of through-holes 730, to permit batch fabrication of alarge number of frame dies 200. Additional detail regarding thedimensions, materials and manufacture of frame wafer 720 are describedherein.

In step 640 frame wafer 720 is mated to base 710, as shown in FIG. 7C.FIG. 7C shows one LEE 210 in each through-hole 730 of frame wafer 720;however, this is not a limitation of the present invention, and in otherembodiments more than one LEE 210 may be disposed within eachthrough-hole 730. In various embodiments, during the manufacturingprocess one or more through-holes 730 may be processed without an LEE210 within the through-hole.

The next step (step 650) in process 600 provides a phosphor (uncured orpartially cured phosphor 740). In one embodiment, phosphor 740 includesor consists essentially of a wavelength-conversion material and abinder. In some embodiments of the present invention, thewavelength-conversion material and binder are mixed prior toapplication, for example in a centrifugal mixer, with or without apartial vacuum over the mixture.

In the next step (step 640) in process 600, phosphor 740 is formed overbase 710, frame wafer 720 and LEEs 210 as shown in FIG. 7D. In someembodiments of the present invention, phosphor 740 is contained orbounded by surface 735 of base 710 and optional sides or barriers 750 asshown in FIG. 7D. In some embodiments of the present invention, barriers750 may be parts of base 710; however, this is not a limitation of thepresent invention, and in other embodiments barriers 750 may be separatefrom base 710. In embodiments in which barrier 750 is not a part of base710, barrier 750 may include or consist essentially of a materialsimilar to that or different from that of base 710. In some embodimentsof the present invention, barrier 750 may be a ring or stencilsurrounding frame wafer 720. In such embodiments, phosphor 740 has abottom surface or face 760 and a top surface or face 765. In someembodiments of the present invention, surfaces 760 and 765 aresubstantially parallel to each other. In some embodiments of the presentinvention, surfaces 760 and 765 are substantially flat and parallel.

Phosphor 740 may be formed by a variety of techniques, for examplecasting, dispensing, spraying, pouring, injecting, injection,compression, transfer or other forms of molding, Mayer bar or draw-downbar, doctor blade, etc. The method of formation of phosphor 740 is not alimitation of the present invention. In some embodiments, base 710 ispositioned such that surface 735 is level, such that when phosphor 740is formed on base 710, surface 735, bottom surface 760 of phosphor 740and top surface 765 of phosphor 740 are parallel or substantiallyparallel, forming a thin layer of phosphor 740 that has a uniform orsubstantially uniform thickness across all or most of the area ofphosphor 740. In some embodiments, one or more barriers 750 are used toprevent or partially prevent the spread of phosphor 740. In someembodiments of the present invention, surface 735 and barriers 750 forma mold for phosphor 740. In some embodiments of the present invention,barriers 750 are portions of a separate component placed over base 710surrounding LEEs 210. In some embodiments of the present invention,barriers 750 are not used. Some embodiments of the present inventionutilize a level base 710 and gravity to automatically produce phosphorlayer 740 with a uniform or substantially uniform thickness. In someembodiments of the present invention, the thickness uniformity ofphosphor 740 is within about ±15%, within about ±10%, within about ±5%,or within about ±1% or less. In one embodiment of the present invention,phosphor 740 covers LEEs 210 and partially fills through-holes 730 inframe wafer 720. In some embodiments of the present invention, phosphor740 covers LEEs 210 and completely fills through-holes 730 in framewafer 720. In some embodiments of the present invention, phosphor 740covers LEEs 210, completely fills through-holes 730 in frame wafer 720and extends above the top of frame wafer 720, as shown in FIG. 7D. Insome embodiments of the present invention, phosphor 740 may extend abovethe top of frame wafer 720 by an amount in the range of about zero toabout 2 mm; however, the amount that phosphor 740 extends above the topof frame wafer 720 is not a limitation of the present invention, and inother embodiments this extension may have other values.

In some embodiments of the present invention, the time between mixingphosphor 740 including or consisting essentially of binder and powderedwavelength-conversion material and disposing phosphor 740 over base 710is relatively short compared to the time required for settling of thepowder in the binder, such that the wavelength-conversion material andbinder form a uniform and homogeneously distributed or substantiallyuniform and homogeneously distributed combination ofwavelength-conversion material in the binder. In some embodiments of thepresent invention, the compositional uniformity of phosphor 740, that isthe distribution of wavelength-conversion material in the binder, isuniform to within about ±15%, within about ±10%, within about ±5%, orwithin about ±1%. Other materials may also be added to phosphor 740 toadvantageously modify its properties. For example, in some embodimentsof the present invention, one or more materials such as fumed alumina orfumed silica may be added to phosphor 740, for example to change itsviscosity or to reduce the settling rate of the wavelength-conversionparticles. In some embodiments of the present invention, in mixtures ofwavelength-conversion material and other optional powders, settlingstarts to occur within about 10 minutes to about 30 minutes, whileapplication of phosphor 740 over base 710 occurs within about 0.25minute to about 5 minutes after mixing. In some embodiments of thepresent invention, the structure shown in FIG. 7D is exposed to apartial vacuum to degas or remove all or a portion of any dissolvedgases in phosphor 740, to reduce or eliminate the number of bubbles inphosphor 740. In some embodiments of the present invention, phosphor 740is exposed to a partial vacuum before formation on base 710. In someembodiments of the present invention, phosphor 740 is formed over base710 in a partial vacuum. In some embodiments of the present invention,base 710 is not level, resulting in phosphor 740 having a non-uniformthickness over base 710 and LEE 210, as discussed herein in more detail.

Phosphor 740 is then cured, producing cured phosphor 230 (step 670) anda composite frame wafer on base 710 as shown in FIG. 7E. Curing mayinclude or consist essentially of heating, exposure to radiation ofvarious sources, for example visible, UV and/or IR light, or chemicalcuring (i.e., introduction of a chemical agent that promotescross-linking of the phosphor binder). In one embodiment of the presentinvention, phosphor 740 is cured by UV or other radiation. In oneembodiment of the present invention, base 710 is held within the curingequipment prior to or just after step 670 of FIG. 6. In some embodimentsof the present invention, in mixtures of binder and powder, settlingstarts to occur within about 10 to about 30 minutes, while curing ofphosphor 740 over base 710 occurs within about 0.10 minute to about 5minutes. In some embodiments of the present invention, steps 660 and 670may take less than about 30 minutes, less than about 10 minutes, lessthan about 5 minutes, or less than about 1 minute. In some embodimentsof the present invention, the curing step 670 includes or consistsessentially of multiple sub-curing steps. For example, a firstsub-curing step may be performed to “freeze” the phosphor particles inthe matrix, and this may be followed by a second sub-curing step tofully cure the binder. In some embodiments of the present invention, thetotal time for forming the phosphor over the base and curing thephosphor may be within about 0.25 minute to about 15 minutes. In someembodiments of the present invention, both the formation and curingprocess may take less than about 4 minutes. In some embodiments of thepresent invention, the second sub-curing step may have a durationbetween about 10 minutes and about 3 hours. In some embodiments of thepresent invention, in the case of thermal curing, the curing process isperformed at between about 100° C. and about 180° C. In some embodimentsof the present invention, the curing process is performed at a lowtemperature of below about 100° C., for example between about 35° C. andabout 100° C. In some embodiments of the present invention, the curingtime for a low-temperature cure process may be between about 1 hour andabout 24 hours. However, the curing time and temperature are notlimitations of the present invention, and in other embodiments othercure times and temperatures may be used. In some embodiments of thepresent invention, curing may include multiple steps, with each stepoptionally having a different time and/or temperature.

In step 680, frame dies 200 are separated or singulated from thestructure shown in FIG. 7E (i.e., a composite frame wafer), resulting inthe structure shown in FIG. 7F. In FIG. 7F the portions of frame wafer720 associated with frame die 200 have been identified as 270, as inFIG. 1A. While FIG. 7F shows each frame die 200 as incorporating one LEE210, this is not a limitation of the present invention, and in otherembodiments frame die 200 includes more than one LEE 210. Frame dies 200may have a size ranging from about 0.25 mm to about 5 mm; however, thesize of frame dies 200 is not a limitation of the present invention. Forexample, a frame die including a large array of LEEs 210 may have alateral dimension of at least 3 mm or at least 7 mm or at least 25 mm.For some frame dies 200, separation may be optional, for example in thecase of large arrays of LEEs 210. Separation of the composite framewafer into individual frame dies 200 may be performed by a variety oftechniques, for example laser cutting, cutting with a knife, diecutting, dicing, saw cutting, water jet cutting, ablation, or the like.In some embodiments, a kerf 770 between frame dies may be less thanabout 200 μm or less than about 100 μm or less than about 50 μm or evenless than 25 μm. This permits very large arrays of frame dies 200 to beformed in a relatively small area with relatively high throughput andrelatively low cost. In some embodiments of the present invention, themolding process leads to very uniform phosphor thickness, resulting inuniform optical characteristics. The ability to form a very large numberof frame dies 200 from a relatively small volume and area of phosphor,in a relatively short time, to avoid or minimize settling of thephosphor powder in the binder, coupled with the relatively highthickness uniformity, leads to very large arrays of frame dies 200having relatively narrow distribution of optical characteristics, suchas chromaticity, color temperature, color rendering index (CRI),luminous flux, etc. and very low manufacture cost. In some embodimentsof the present invention, an entire wafer of LEEs 210 may be batchprocessed simultaneously using this approach. For example LEEs 210 maybe produced on a 2″ or 4″ or 6″ or larger diameter wafer. After LEEs 210are fabricated and singulated (here singulation refers to singulation ofthe substrate on which LEEs 210 are formed), they may be transferred tomold substrate 710 for a frame die process detailed herein. In someembodiments of the present invention, the entire wafer amount of LEEs210 may be transferred in batch mode (i.e., together) to mold substrate710, for example using a tape-to-tape transfer process. In otherembodiments, LEEs 210 may be transferred to mold substrate 710die-by-die or in groups of dies.

In some embodiments of the present invention, separation (i.e., of theframe dies) takes place before removal from base 710 while in otherembodiments base 710 is removed before separation, as discussed in moredetail herein. In some embodiments of the present invention, phosphor230 includes or consists essentially of only a transparent binder thatis transparent to a wavelength of light emitted by LEEs 210.

In some embodiments of the present invention, the frame die 200 shown inFIG. 7F may be transferred to another substrate 711 such that contacts220 are accessible, as shown in FIG. 7G. Such a transfer may beperformed using transfer tape, a pick-and-place tool with a die flipper,or any other technique. In some embodiments of the present invention,this transfer may be done in batch mode, while in other embodiments itmay be done die-by-die or in groups of dies. In some embodiments of thepresent invention, the transfer may be performed before singulation ofthe frame wafer. The result of this process is one or more frame die200, as shown in FIG. 1A. In various embodiments, the process provides abatch method to produce dies integrated with phosphor, with uniformphosphor over each die, in a cost-effective way.

Frame dies 200 may then be removed from base 710 or substrate 711 forplacement on a substrate or circuit board. In some embodiments of thepresent invention, frame dies 200 may be mounted into a separatepackage.

In some embodiments of the present invention, only one phosphor 740 isused; however, this is not a limitation of the present invention, and inother embodiments multiple phosphors are used. In some embodiments ofthe present invention, phosphor 740 may include or consist essentiallyof multiple different phosphor powders. In some embodiments of thepresent invention, a first phosphor 740 is deposited and cured orpartially cured, followed by the deposition and curing of one or moresuccessive phosphors. In some embodiments of the present invention, abinder is deposited and cured or partially cured, and the binder istransparent to a wavelength of light emitted by LEE 210 and/or phosphor740 or 230, followed by the deposition and curing of one or morephosphors 740, to form a layered structure in which one or more layersmay have a phosphor composition, type and/or thickness different fromeach other. In this way, a remote-phosphor frame die may be fabricated,for example as shown in FIGS. 4A-4C.

FIG. 7H shows a portion of an alternate process embodiment in whichframe 720 is mated to base 710 before placement of LEEs 210 on base 710.FIG. 7H shows the process at an early stage of manufacture, at whichpoint frame 720 has been mated to base 710. The next step is to placeLEEs 210 on base 710 in through-holes 730, resulting in the structureshown in FIG. 7C. In some embodiments of the present invention, LEEs 210may be placed within through-holes 730 on base 710 one at a time, forexample using a pick-and-place operation. In some embodiments of thepresent invention, LEEs 210 may be placed within through-holes 730 in abatch process.

In some embodiments of the present invention, the structure shown inFIG. 7D may have a cover 780 over and in contact with uncured phosphor740, as shown in FIG. 7I. In some embodiments, cover 780 may be flat orsubstantially flat, as shown in FIG. 7I, to produce a structure similarto that shown in FIG. 1A. However, this is not a limitation of thepresent invention, and in other embodiments cover 780 may be shaped toproduce structures having a shaped phosphor 230, for example similar tostructures shown in FIGS. 1H, 1I, 1J, and 1K. Some examples of differentshapes include a hemisphere, a portion of a hemisphere, a paraboloid, aFresnel optic, or a photonic crystal; however, the specific shape is nota limitation of the present invention, and in other embodiments thephosphor may have any shape.

FIG. 7J shows an embodiment of the present invention similar to thestructure of FIG. 7I but with a mold cover 780 featuring depressions 781that may be used to form a frame die similar to that shown in FIG. 1H.As shown, depressions 781 are regions recessed below the remainingsurface of mold cover 780. While each depression 781 in FIG. 7J is shownas having a smooth, curved surface, this is not a limitation of thepresent invention, and in other embodiments depressions 781 may includeor consist essentially of one or more flat surfaces or have any shape.In some embodiments of the present invention, mold cover 781 may includeprotrusions 782 (i.e., regions extending beyond the remaining surface ofmold cover 780), as shown in FIG. 7K, that may be used to produce aframe die similar to that shown in FIG. 1O. While each protrusion 782 inFIG. 7K is shown as having a flat surface, this is not a limitation ofthe present invention, and in other embodiments, protrusions 782 mayinclude or consist essentially of one or more curved surfaces or haveany shape.

In some embodiments, all or a portion of cover 780 or mold substrate 710adjacent to phosphor 740 may be covered by (e.g., coated with) a moldrelease material. In some embodiments, the mold release material is amold release film. In some embodiments, the mold release material ormold release film may be patterned, roughened, or textured to, e.g.,impart similar features on all or portions of the outer surface ofphosphor 230. In some embodiments, the mold release material or moldrelease film may be smooth or substantially smooth.

In some embodiments of the present invention, a textured or non-smoothsurface of phosphor 230 reduces total internal reflection (TIR) withinphosphor 230 and achieves improved light extraction. In some embodimentsof the present invention, a non-smooth surface of phosphor 230 may havea periodic structure; however, this is not a limitation of the presentinvention, and in other embodiments the structure may be random. In someembodiments of the present invention, a non-smooth surface of phosphor230 may include light-extraction features (e.g., raised bumps and/ordepressions) having a dimension in the range of about 0.25 μm to about15 μm. In some embodiments of the present invention, thelight-extraction features may be hemispherical or pyramidal in shape;however, this is not a limitation of the present invention, and in otherembodiments the light-extraction features may have any shape. In someembodiments of the present invention, the light-extraction feature is arandom texture or roughness with an average roughness in the range ofabout 0.25 μm to about 15 μm.

In some embodiments of the present invention, providing and curingphosphor 740 to form cured phosphor 230 may be performed in a moldingtool. For example, the process may include or consist essentially ofinjection molding, transfer molding, compression molding, casting etc.Compression molding may be carried out using equipment such as a LCM1010manufactured by Towa Corporation.

In some embodiments of the present invention, a partial vacuum may beused to enhance transport of phosphor 740 into and to fully fill thedepressions formed by through-holes 730 on mold substrate 710, and topartially or fully degas phosphor 740 before curing.

In some embodiments of the present invention, the phosphor may be shapedby the process described in reference to FIGS. 7I-7L. In otherembodiments of the present invention, the phosphor may be shaped byforming a composite frame wafer as shown in FIG. 7E or a frame die asshown, for example in FIG. 1A, 1D, or 1E, and then removing one or moreportions of the phosphor to produce a shape different from the startingshape. Removal of one or more portions of the phosphor may beaccomplished using a variety of techniques, for example knife cutting,dicing, laser cutting, die cutting, or the like.

In some embodiments of the present invention, a thin portion or web 231of phosphor 230 may be formed between adjacent frame dies, as shown inFIG. 1P and FIG. 7L. In some embodiments of the present invention, thismay ease singulation by reducing the amount of phosphor that needs to besingulated with the material of frame wafer 720. In some embodiments ofthe present invention, singulation may be performed in more than onestep, for example initially singulating the phosphor and thensingulating frame wafer 720.

In some embodiments of the present invention, formation of phosphor 740in step 660 may not completely fill up the recess in frame 720. Forexample, FIG. 7M shows the structure of FIG. 7C at a later stage ofmanufacture, in which phosphor 740 coats portions of frame 720 and LEE210, but does not completely fill up the recess in frame 720. In someembodiments the structure of FIG. 7M may be cured and singulated, whilein other embodiments one or more additional phosphor layers may beformed over cured or partially cured phosphor 740, for exampleidentified in FIG. 7N as phosphor 230. After phosphor 230 is cured,phosphor 741 may be formed over cured or partially cured phosphor 230,resulting in the structure of FIG. 7N. The structure of FIG. 7N may thenbe cured to cure phosphor 741 and subsequently singulated, resulting inthe structure of FIG. 7O, where phosphor 230 corresponds to phosphor 740after curing and phosphor 230′ corresponds to phosphor 741 after curing.

In some embodiments of the present invention, more than one layer ofphosphor may be formed over LEE 210 within frame 270, as shown in FIG.7P. In some embodiments of the present invention, the structure of FIG.7P shows the structure of FIG. 7E at a later stage of manufacture. Afterphosphor 740 of FIG. 7E is cured or partially cured, identified asphosphor 230 in FIG. 7P, phosphor 740′ may be formed over phosphor 230and cured, resulting in the structure shown in FIG. 4A aftersingulation. Referring to FIG. 4C, in some embodiments of the presentinvention phosphor 410 may include or consist essentially of transparentbinder, without any wavelength-conversion material, while phosphor 230includes or consists essentially of binder and wavelength-conversionmaterial. In some embodiments of the present invention, phosphors 230and 410 both include or consist essentially of binder andwavelength-conversion material, where binder and/or thewavelength-conversion material in phosphor 230 is different from that inphosphor 410.

In some embodiments of the present invention, frame dies 200 includingor consisting essentially of two or more types of phosphor may bemanufactured in stages. In the first stage a process similar to thatshown in FIGS. 7A-7E is carried out. Following this, a second stage ofphosphor formation is implemented. In some embodiments of the presentinvention, in a second stage a flat or shaped portion of phosphor isformed separately, for example using similar techniques described hereinwith respect to phosphor formation in frame wafer 720, for exampleincluding casting, molding, transfer molding, injection molding,compression molding, or the like. In some embodiments, binder is formedfirst. In a separate process the binder containing wavelength-conversionmaterial, identified as a phosphor sheet, is formed. The phosphor sheetis then mated to the frame structure.

In some embodiments of the present invention, the process starts withthe structure of FIG. 7D. In a separate process, a second phosphor sheetis formed. In some embodiments of the present invention, phosphor 740 ofFIG. 7D is partially cured and phosphor sheet 792 is mated to uncured,partially cured or cured phosphor 740, as shown in FIG. 7Q. Thestructure of FIG. 7Q is then cured, causing phosphor sheet 792 to adhereto cured phosphor 740, and singulated, resulting in the structure ofFIG. 4F. In some embodiments of the present invention, a transparentoptical adhesive or glue, or thin intermediate layer of binder may beused to attach phosphor sheet 792 to phosphor 740. While the structureshown in FIG. 7Q produces frame dies as shown in FIG. 4F, the flat shapeof phosphor sheet 792 is not a limitation of the present invention, andin other embodiments phosphor sheet 792 may be shaped, as shown forphosphor sheet 793 in FIG. 7R. In a variation of this embodiment of thepresent invention, the recesses in frame 720 may only just be filledwith phosphor 740, as shown in FIG. 7R, and mated with phosphor sheet793 to produce the structure of FIG. 4B after singulation.

While the processes described with reference to FIGS. 7Q and 7R are fora two-stage approach, this is not a limitation of the present invention,and in other embodiments more than one phosphor sheet may be utilized.For example, two or more phosphor sheets may be made in separateprocesses and then mated together as discussed herein. This stagedapproach has the advantage of separating the formation of thewavelength-conversion material from the remainder of the process. Thethickness and concentration of wavelength-conversion material within thebinder may strongly impact the optical characteristics of frame die 200,for example CCT, CRI, angular color uniformity, R9, and the like. Thus,making the phosphor sheet, which includes or consists essentially ofbinder and wavelength-conversion material, in a separate process maylead to a relatively more uniform concentration of wavelength-conversionmaterial in the binder and a relatively more uniform thickness,resulting in improved uniformity of optical characteristics, within acomposite frame wafer and between different composite frame wafers, andthus among an entire population of frame dies.

FIG. 8A shows a cross-sectional view of the structure of FIG. 8B alongcut line A-A′. Frame wafer 720 may include or consist essentially of oneor more of a variety of materials. Various techniques for manufactureand materials for frame wafer 720 are discussed herein. In someembodiments of the present invention, frame wafer 720 includes an arrayof through-holes 730. In some embodiments, all through-holes 730 havethe same shape and size; however, this is not a limitation of thepresent invention, and in other embodiments frame wafer 720 may includethrough-holes 730 having different sizes and shapes. In some embodimentsof the present invention, through-holes 730 are arranged in a regulararray, with the same distance between each through-hole 730, as shown inFIG. 8B; however, this is not a limitation of the present invention, andin other embodiments through-holes may be arranged in any type of arrayor pattern. The example shown in FIG. 8B shows a 3×3 array ofthrough-holes 730; however, this is not a limitation of the presentinvention, and in other embodiments other array sizes may be employed.In some embodiments of the present invention, frame wafer 720 may havemore than 100 through-holes 730, more than 1000 through-holes 730, ormore than 10,000 through-holes 730. The number of through-holes 730 inframe wafer 720 is not a limitation of the present invention.

Through-holes 730 have sidewalls 272, which form an angle 279 withsurface 810 of frame wafer 720. Angle 279 may have a wide range ofvalues, for example from just above zero degrees to just below 180degrees. In one embodiment, angle 279 has a value in the range of about10° to about 90°. In another embodiment, angle 279 has a value in therange of about 10° to about 60°.

Frame 270 has a top opening and a bottom opening. In some embodiments ofthe present invention, top and bottom openings may have the same orsubstantially the same shape. In some embodiments, as shown in FIGS. 8Aand 8B, the top opening is rectangular, having a length and width of 820and 820′, and the bottom opening is rectangular and has a length andwidth of 265 and 265′, respectively. In some embodiments of the presentinvention, dimensions 820 and 820′ are the same or substantially thesame as dimensions 267 and 267′ respectively of FIG. 1B. In someembodiments of the present invention, the top opening is square, inwhich case dimensions 820 and 820′ are the same or substantially thesame. In some embodiments of the present invention, the bottom openingis square, in which case dimensions 265 and 265′ are the same orsubstantially the same.

In some embodiments of the present invention, the bottom dimension 265,265′ of through-hole 730 may be given approximately by the sum ofdimension 212, 212′ of LEE 210 and twice the gap 242 (FIGS. 1A-1C). Forexample, for LEE 210 having dimension 212 of about 180 μm and gap 242having a value of about 5 μm, bottom dimension 265 of through-hole 730is about 190 μm. In some embodiments of the present invention, LEE 210has dimension 212 of about 1000 μm and gap 242 has a value of about 10μm, resulting in a bottom dimension 265 of through-hole 730 of about1020 μm. In some embodiments of the present invention, bottom dimension265 may have a value in the range of about 150 μm to about 5 mm.

In some embodiments of the present invention, through-holes 730 arearranged in a regular periodic array having a distance between the topsof through-holes 730 of 870 in one direction and 870′ in an orthogonaldirection, as shown in FIG. 8B. In some embodiments, the value ofdistance 870 is the same as or substantially the same as the value ofdistance 870′. In some embodiments, distances 870 and/or 870′ may have avalue in the range of about zero (in which case through-holes 730 abuteach other) to about 1 mm, e.g., in the range of about zero to about 0.5μm. In some embodiments of the present invention, distances 870 and 870′are determined by the amount of space required between through-holes 730for subsequent singulation. In some embodiments of the presentinvention, dimensions 870, 870′ may be substantially zero, in which caseeach through-hole abuts its neighbor(s). In some embodiments of thepresent invention, dimensions 870, 870′ may be in the range of about 10μm to about 2000 μm, or preferably in the range of about 25 μm to about500 μm.

In some embodiments of the present invention, through-holes 730 may havea square shape, or a rectangular shape, while in other embodimentsthrough-holes 730 may have any arbitrary shape. In some embodiments ofthe present invention, the shape of the bottom of through-hole 730 issubstantially the same as that of the LEE(s) 210 that will be disposedwithin through-hole 730. FIGS. 8A and 8B show the shape of the top andbottom of through-hole 730 as being the same or substantially the same;however, this is not a limitation of the present invention, as shown inFIG. 8C. FIG. 8C shows an embodiment of the present invention in whichthe bottom of through-hole 730 has a square shape and the top ofthrough-hole 730 has a circular shape. The relative shapes of the topand bottom of through-hole 730 are not limitations of the presentinvention, and in other embodiments the top of through-hole 730 may haveany shape and may be different than the shape of the bottom ofthrough-hole 730, which may also have any shape.

In some embodiments of the present invention where sloped walls 272 havea flat surface forming an angle 279 with surface 810, and where LEE 210has a square or rectangular shape, the process shown in FIG. 9 may beused to determine the size and spacing of through-holes 730. Process 900is shown having six steps; however, this is not a limitation of thepresent invention, and in other embodiments the invention has more orfewer steps and/or the steps may be performed in different order. Theprocess starts in step 910 with the determination of the dimensions ofthe LEE 210 to be utilized. For example, LEE 210 may have length andwidth of 212 and 212′ respectively. In step 920, the gap width 242 isdetermined. In step 930, the length 265 and width 265′ of the bottom ofthrough-hole 730 is determined as follows:Length265(Length of bottom of through-hole730)=2×GW₂₄₂ +L _(LEE210)Width265′(Width of bottom of through-hole730)=2×GW_(242′) +W _(LEE210)where GW₂₄₂ represents gap width 242 and W_(LEE210) and L_(LEE210)represent the width 212′ and length 212 of LEE 210 respectively. In step940, the thickness 252 of frame wafer 710 is determined. In step 950,the value of angle 279 is determined. In step 960, the length 820 andwidth 820′ of the top of through-hole 730 are determined. In oneembodiment this is determined from the equations:820(Length of top ofthrough-hole730)=Length265+2×(Thickness252/tan(Angle279)820′(Width of top ofthrough-hole730)=Width265′+2×(Thickness252/tan(Angle279)

In these examples, the gap width 242 is the same on all sides of LEE210; however, this is not a limitation of the present invention, and inother embodiments the gap width 242 may be different on different sidesof LEE 210.

In some exemplary embodiments of the present invention, frame wafer 720has a thickness 252 in the range of about 10 μm to about 3000 μm, abottom hole length 265 and bottom hole width 265′ in the range of about100 μm to about 5000 μm, a top hole length 820 and a top hole width 820′in the range of about 100 μm to about 7000 μm, and/or an angle 279 inthe range of about 10° to about 75°. As discussed herein, interactionsbetween various dimensions may result in changes in optical performanceand optimal or relatively optimal combinations of various dimensions mayresult in relatively improved electrical, optical, and mechanicalcharacteristics.

Frame wafer 720 and frame 270 may be formed using a variety oftechniques and from a variety of materials. In some embodiments of thepresent invention, frame 270 and/or frame wafer 720 may include orconsist essentially of at least one of sapphire, fused quartz,borosilicate glass, glass, ceramic, metal, polymer, polymer,acrylonitrile butadiene styrene (ABS), acrylic, thermoplastics such aspolyoxymethylene (e.g., Delrin), high-density polyethylene (HDPE),polycarbonate (e.g., Lexan), poly(methyl methacrylate) (e.g., Lucite), ablend of polyphenylene ether (PPE) resin and polystyrene (e.g., Noryl),nylon, polyethylene terephthalate (PET), polyether ether ketone (PEEK),polyethylene, polyimide, polypropylene, polystyrene, polyvinyl chloride(PVC), silicone, epoxy, or the like.

In some embodiments of the present invention, frame 270 and/or framewafer 720 may include or consist essentially of a polymer or plastic. Insome embodiments of the present invention, plastic frame 270 may bemanufactured using one or more of the following techniques: ablation,molding, injection molding, compression molding, transfer molding,machining, rapid prototyping, three-dimensional printing, or the like.

In various embodiments of the present invention, frame 270 and/or framewafer 720 may include or consist essentially of glass, quartz, sapphire,aluminum oxide, aluminum oxynitride (AlON), silicon carbide, and/orother transparent oxides or polymers, for example silicone or epoxy. Invarious embodiments of the present invention, frame 270 and/or framewafer 720 may include or consist essentially of low-temperature glass,an example of such material is Hitachi Chemical's low-melting vanadateglass series. In various embodiments of the present invention, a glassframe 270 may be manufactured using one or more of the followingtechniques: wet chemical etching, dry etching, reactive ion etching,molding, casting, ablation, bonding, machining, rapid prototyping,three-dimensional printing, ultrasonic machining, abrasive machining, orthe like.

In some embodiments of the present invention, frame 270 and/or framewafer 720 may include or consist essentially of a metal, for examplealuminum (Al), copper (Cu), silver (Ag), gold (Au), or the like. In someembodiments of the present invention, a metal frame 270 may bemanufactured using one or more of the following techniques: ablation,molding, stamping, machining, rapid prototyping, casting, or the like.

In some embodiments of the present invention, frame 270 and/or framewafer 720 may be formed from a crystalline semiconductor material, forexample silicon, gallium arsenide, indium phosphide or the like. In someembodiments of the present invention, frame 270 and/or frame wafer 720may be formed using semiconductor micromachining techniques, for examplelithographic patterning, wet chemical etching, dry etching, anisotropicetching, isotropic etching, or material deposition by, for example,evaporation, sputtering, chemical vapor deposition, or the like.

In some embodiments of the present invention, frame 270 and/or framewafer 720 may be processed after formation to improve characteristicssuch as surface smoothness, mechanical and chemical properties and thelike. In some embodiments of the present invention, said process mayinclude or essentially consist of thermal processes such as heating tonear glass transition temperature or rapid thermal annealing.

In some embodiments of the present invention, frame 270 and/or framewafer 720 may include or consist essentially of silicon and be formedfrom a substantially single crystal-silicon wafer using siliconmicro-machining techniques. In some embodiments of the presentinvention, frame 270 may be manufactured from a (001)-oriented siliconwafer using anisotropic etching (e.g., wet etching with an etchantincluding or consisting essentially of potassium hydroxide (KOH), EDP(an aqueous mixture of ethylene diamine and pyrocatechol), and/ortetramethylammonium hydroxide (TMAH) to form the sloped surfaces of theframe, having an angle 279 of about 54.7°, formed by the intersection of(111) and (001) planes in the crystal structure of the silicon wafer.

FIG. 10 is a flow chart of a process 1000 for forming a frame wafer 720using anisotropic etching of a semiconductor wafer. Process 1000 isshown having four steps; however, this is not a limitation of thepresent invention, and in other embodiments the invention has more orfewer steps and/or the steps may be performed in different order. Instep 1010, a semiconductor wafer is provided. In step 1020, the wafer ismasked with a masking agent such as, e.g., photoresist. In step 1030 themask is patterned to provide openings in the masking agent for etchingthe wafer in step 1040. In step 1040, the wafer is etched at theopenings to form through-holes 730. Optionally, the masking agent may beremoved or partially removed from the frame wafer.

FIG. 11A shows one embodiment of the present invention of a process toproduce a frame wafer 720 using an anisotropic etchant. In thisembodiment, the process starts with a (001)-oriented silicon wafer 1110as shown in FIG. 11A. The wafer is coated with an etch mask 1120, asshown in FIG. 11A. Etch mask 1120 may include or consist essentially ofone or more of the following: photoresist, silicon oxide, siliconnitride, polyimide, metal, or the like. In one embodiment of the presentinvention, etch mask 1120 includes or consists essentially of siliconnitride. In one embodiment of the present invention, etch mask 1120includes or consists essentially of a layer of silicon oxide overcoatedwith a layer of silicon nitride. The required thickness of etch mask1120 may be determined without undue experimentation, based on theetchant used in subsequent steps. In some embodiments of the presentinvention, layer 1120 has a thickness in the range of about 10 nm toabout 4 μm, or in the range of about 100 nm to about 2 μm. In FIG. 11Athe back and edges of silicon wafer 1110 are coated with etch mask 1120;however, in other embodiments this may not be necessary.

FIG. 11B shows the structure of FIG. 11A at a later stage ofmanufacture, in which openings 1130 have been formed in etch mask 1120.In one embodiment, openings 1130 may have a square or rectangular shape;however, in other embodiments openings 1130 may have different shapes.When anisotropic etchants such as KOH, TMAH and or EDP are used it maybe preferable for openings 1130 to have square or rectangular shapes.

FIG. 11C shows the structure of FIG. 11B at a later stage ofmanufacture, in which silicon wafer 1110 has been etched using ananisotropic etchant to create holes 1140, corresponding to through-holes730 in FIG. 7B. In FIG. 11C, portions of mask 1120 remain covering thebottoms of holes 1140, while in other embodiments these portions of mask1120 may be removed during the etching process. If they are not removedduring the etching process, they may be removed subsequently, leavingthe frame wafer structure 720 of FIG. 11D. In this embodiment, holes1140 are shaped like truncated pyramids, having angle 279 with a valueof about 54.7°. Mask 1120 is shown as having been removed in FIG. 11D;however, in other embodiments mask 1120 may remain in place or partiallyin place on the surface of silicon wafer 1110, as long as it does notcover the bottoms of holes 1140. In some embodiments of the presentinvention, silicon wafer 1110 may be thinned before or after formationof holes 1140. The thinning process may be performed chemically,mechanically, or physically or by using a combination of said methods,and may include or essentially consist of etching, polishing, grinding,chemical mechanical polishing (CMP) or the like; however this is not alimitation, and in some embodiments of the present invention thinningmay be performed by other techniques.

FIG. 11E shows a plan view of the structure of FIG. 11D, where thestructure of FIG. 11D is a cross-section of the structure shown in FIG.11E through cut line A-A′. As may be seen in FIG. 11E, after the processshown in FIG. 11D, the silicon wafer has an array of through-holes 1140with sloped sidewalls 272.

In some embodiments of the present invention, silicon wafer 1110 mayhave a relatively high resistivity, for example greater than about 100ohm-cm or greater than about 10⁴ ohm-cm. In some embodiments of thepresent invention, silicon wafer 1110 may be conductive and may bep-type or n-type. In some embodiments of the present invention, ifsilicon wafer 1110 is conductive, it may be desirable to cover all or aportion of the bottom of frame 270 such that current does not conductthrough frame 270, as discussed herein. In some embodiments of thepresent invention, frame 270 and/or frame wafer 720 may include orconsist essentially of a material or materials other than silicon. Insome embodiments of the present invention, frame wafer 720 may includeor consist essentially of a different crystalline material, for examplesemiconductors based on gallium arsenide, aluminum arsenide, indiumarsenide, gallium nitride, aluminum nitride, indium nitride, indiumphosphor, gallium phosphor, or alloys of these materials or the like.

In some embodiments of the present invention, frame 270 and/or framewafer 720 may be manufactured by other means than anisotropic etchingusing a wet chemical anisotropic etchant. For example, in someembodiments of the present invention, frame 270 and/or frame wafer 720may be manufactured from silicon or other semiconductors using one ormore of the following techniques; isotropic etching, wet chemicaletching, dry etching reactive ion etching, ablation, wafer bonding,chemical vapor deposition, or epitaxy. The method of forming frame 270and/or frame wafer 720 is not a limitation of the present invention.

While examples herein have described frame 270 and/or frame wafer 720 asincluding or consisting essentially of a semiconductor, metal, glass orplastic, the material of construction of frame 270 and/or frame wafer720 is not a limitation of the present invention, and in otherembodiments other materials may be used. While examples herein havedescribed frame 270 and/or frame wafer 720 as including or consistingessentially of a single material, this is not a limitation of thepresent invention, and in other embodiments frame 270 and/or frame wafer720 may include or consist essentially of more than one material. Forexample, in one embodiment of the present invention, frame 270 and/orframe wafer 720 may include or consist essentially of layers ofdifferent materials. In some embodiments of the present invention, frame270 and/or frame wafer 720 may include or consist essentially ofcombinations of more than one material. In some embodiments, frame 270and/or frame wafer 720 may be formed by molding, casting, or the like.

In some embodiments of the present invention, it may be desirable forportions of frame 270 that are exposed to light emitted from LEE 210 andphosphor 230 to have a high reflectance to a wavelength of light emittedby LEE 210 and/or phosphor 230. In some embodiments of the presentinvention, the reflectance may be greater than 80%, greater than 90%,greater than 95%, or greater than 98%. In general, the higher thereflectance, the less light loss occurs within frame die 200, resultingin a higher efficacy.

In some embodiments of the present invention, frame 270 is formed of amaterial having a high reflectance to a wavelength of light emitted byLEE 210 and/or phosphor 230. For example frame 270 may include orconsist essentially of one or more high reflectance polymer or plasticmaterials, for example MS2002 manufactured by Dow Corning or CEL-W-7005or CEL-W-8000 white molding compound manufactured by Hitachi Chemical,or the like. MS2002 has a reflectance over substantially all of thevisible wavelength range of about 97%, while CEL-W-7500 has areflectance over substantially all of the visible wavelength range ofabout 93%.

In some embodiments of the present invention, the material of frame 270may have a reflectance that is not sufficiently high, and in some ofthese embodiments all or portions of frame 270 may be coated with areflective (or “reflecting”) coating having sufficient reflectivity fora wavelength of light emitted by LEE 210 and/or phosphor 230. In someembodiments of the present invention, the coating may include or consistessentially of one layer, while in other embodiments the coating mayinclude or consist essentially of more than one layer. In someembodiments of the present invention, the reflecting coating may includeone or more metal layers, for example including or consistingessentially of one or more materials including aluminum, copper, gold,silver, chromium, or the like. In some embodiments of the presentinvention, the reflecting coating may include one or more dielectriclayers, for example silicon dioxide, titanium dioxide, silicon nitride,or the like. In some embodiments of the present invention, thereflecting coating may include or consist essentially of a Braggreflector. In some embodiments, the reflecting coating may include orconsist essentially of one or more metal layers and one or moredielectric layers. The materials of the reflecting coating and themethods of forming the reflecting coating are not a limitation of thepresent invention.

In some embodiments of the present invention, LEEs 210 are fabricated inwafer form (i.e., as portions of a semiconductor wafer). A wafer mayinclude about 5000 or more LEEs 210. In some embodiments, a waferincludes over about 20,000, over 100,000, or over 500,000 LEEs 210.After fabrication of LEEs 210, all or some of the LEEs 210 are testedand sorted into bins based on one or more characteristics, for exampleoptical or electrical characteristics, where each bin includes a portionof the total population. Bins may include, for example, emissionwavelength, forward voltage, light output power, or the like. Theparticular choice of one or more bins or range of values within the oneor more bins is not a limitation of the present invention. In oneembodiment, LEEs 210 are binned by emission wavelength. The processshown in FIG. 6 may then be carried out on each bin of LEEs 210. Thecomposition and amount of phosphor applied over base 710 and LEE 210 isdetermined in advance to achieve the desired color point, chromaticity,color temperature, CRI or other optical properties, based on theemission wavelength of each bin. In this embodiment, each bin may have adifferent composition and/or thickness of phosphor to achieve thedesired optical properties. In one embodiment, the phosphor compositionand thickness are adjusted based on the bin information to achieve arelatively more narrow distribution in optical properties (for example,color temperature) than would be achievable without binning.

In some embodiments of the present invention, LEEs 210 are fabricated inwafer form (i.e., as portions of a semiconductor wafer). A wafer mayinclude over about 5000 or more LEEs 210. In some embodiments, a wafermay include over about 20,000 or over 100,000 LEEs 210. Afterfabrication of LEEs 210, all LEEs 210 are tested, or some of LEEs 210 onone or more wafers are tested. In one embodiment, the process shown inFIG. 6 is then carried out on all LEEs 210 from the wafer, or at leastall LEEs 210 determined to be functional and/or within desiredspecifications. The composition and amount of phosphor applied over base710 and LEE 210 is determined in advance to achieve the desired colorpoint, color temperature, CRI or other optical properties, based on thetest results of all or some LEEs 210 on that wafer. This phosphor mayinclude or consist essentially of one or more phosphor powders orwavelength-conversion materials.

In some embodiments, there is no testing done on LEEs 210 prior toapplication of the phosphor over LEEs 210. In some embodiments, thestarting wafer is applied to dicing tape, after which the wafer issingulated into LEEs 210. The tape preferably has the ability to expandand is expanded to provide the required spacing between LEEs 210 tomatch the through-hole spacing in frame wafer 720. In one embodiment,the spacing between LEEs 210 is such that after expansion, each LEE 210fits into a through-hole 730 in frame wafer 720 during step 640 ofprocess 600. An example of such an expansion tape is SWT20+ manufacturedby Nitto Denko.

In some embodiments of the present invention, the singulation isperformed with the contacts down on (i.e., adjacent to) the tape, andthe tape may be used as base 710. If the singulation is performed withthe contacts up (not adjacent to the tape), LEEs 210 may be transferredusing transfer tape or other transfer methods to flip their orientation.In the tape-transfer operation, a second substrate or tape is applied tothe exposed side (here contact side) of LEEs 210 and the first tape isremoved. A variety of techniques may be used for such transfer, forexample using tapes of different tack levels, thermal release tape,and/or UV release tape. An advantage of this approach is that LEEs 210are then positioned correctly on base 710 without any need for a serialpick-and-place process, saving time and expense. In another embodiment,LEEs 210 may be placed on base 710 at the correct spacing, usingsemi-batch or serial techniques, for example pick-and-place.

FIGS. 12A-12D depict a schematic of one embodiment of this process. InFIG. 12A, a tape 1220 is applied to the back of a wafer 1210 (in thisexample the contacts 220 are face up). FIG. 12B shows the structure ofFIG. 12A at a later stage of manufacture. In FIG. 12B wafer 1210 hasbeen singulated, resulting in LEEs 210 on tape 1220. A spacing 1230between LEE 210 may be determined by the singulation process, asdescribed herein. In some embodiments, spacing 1230 is in the range ofabout 5 μm to about 200 μm. FIG. 12C shows the structure of FIG. 12B ata later stage of manufacture. In FIG. 12C, the tape 1220 has beenoptionally expanded or stretched. Spacing 1230, identified as spacing1230′ after expansion, is set to the desired value for making framedies, as described above, by the expansion process. That is, tape 1220is expanded until the spacing between adjacent LEEs 210 (identified as1230′ in FIG. 12C) is appropriate to make frame dies 200 having adesired thickness of phosphor thereon. FIG. 12D shows the structure ofFIG. 12C at a later stage of manufacture. In FIG. 12D a second tape 1240is applied to the contact side of LEEs 210. Finally, first tape 1220 isremoved, leaving the structure shown in FIG. 7A (spacing 1230′ in FIG.12D corresponds to spacing 705 in FIG. 7A), whereupon the processdescribed in reference to FIGS. 7A-7F or other processes may be carriedout. In some embodiments of the present invention, tape 1240 is the baseor mold substrate 710 shown in FIG. 7A.

In some embodiments of the present invention, the process begins withthe structure shown in FIG. 7E or FIG. 7F. In some embodiments, LEEs 210have been binned, while in other embodiments LEEs 210 have not beenbinned or may have not been tested. In some embodiments one or moreportions of LEEs 210 have been tested. The process by which LEEs 210 areselected for the structure shown in FIG. 7E is not a limitation of thepresent invention. The structure shown in FIG. 7E may be called a“composite frame wafer,” including or consisting essentially of multipleLEEs 210, frames 720, and phosphors 230 before singulation. Thestructure in FIG. 7F depicts a composite frame wafer after singulation,including multiple frame dies 200 on mold substrate 710.

In some embodiments, frame dies 200 are tested either in composite framewafer form (shown, for example, in FIG. 7E) or in singulated form(shown, for example, in FIG. 7F). Testing may be performed by applying acurrent and voltage to contacts 220 and measuring the emitted light. Inone embodiment, contacts 220 are accessed for testing by probes orneedles that poke or penetrate through tape 710. In other embodiments,testing is performed by first transferring the structure in FIG. 7E orframe dies 200 in FIG. 7F to another carrier such that contacts 220 areface up and directly accessible. Such a transfer may be performed in abatch process, similar to that using transfer tape described inconjunction with FIGS. 12A-12D, or may be performed in a semi-batchprocess or a serial process, such as pick-and-place. Once the structurefrom FIG. 7E or frame dies 200 (for example as depicted in FIG. 7F) areoriented with the contacts accessible, they may be tested usingconventional test equipment, for example manual, semi-automatic or fullyautomatic test equipment that applies a current and voltage to LEEs 210,and measuring the light properties of frame dies 200. In someembodiments of the present invention, characteristics that may bemeasured include CCT, CRI, spectral power density, R9, voltage, currentluminous flux, radiant flux, angular color uniformity, or the like. Insome embodiments of the present invention, the composite frame wafer ofFIG. 7E or frame dies 200 of FIG. 7F may be characterized in wafer form,similar to what is done with conventional semiconductor wafers. In someembodiments, the composite frame wafer may be sufficiently rigid forsuch processing, while in other embodiments an additional backingmaterial or plate or carrier may be used provide additional rigidity sothat the composite frame wafer may be handled and tested in a fashionand using equipment similar to that used for wafers of semiconductordevices.

In some embodiments of the present invention, after testing, frame dies200 are physically sorted and binned. This may result in multiple binshaving different optical properties that may then be used for differentproducts. In some embodiments, the bins correspond to different valuesof color temperature, luminous flux, forward voltage (at a specificcurrent), CCT, CRI, R9, or the like.

In some embodiments of the present invention, after testing, frame dies200 are virtually sorted and binned. In accordance with preferredembodiments, virtual sorting and binning means that a map of thecharacteristics of each frame die 200 on the wafer (that is for exampledepicted in FIG. 7E or FIG. 7F) is produced, and frame dies 200 are putinto, or assigned, to virtual bins based on their optical and/orelectrical properties, for example color temperature, luminous flux orforward voltage. In some embodiments, the bin map of the wafer is (i.e.,a map of the specific characteristic as a function of location on thewafer) used to select frame dies 200 having specific characteristics fora particular product. The remaining frame dies 200 from other bins maythen be used in a different product at a different time. In someembodiments, frame dies 200 are used without testing or binning.

In some embodiments of the present invention, if the starting point ofthe process is the structure shown in FIG. 7E, the structure may besingulated to form frame dies 200 before or after testing. Furthermore,before either physical or virtual frame die 200 binning, the compositeframe wafer (FIG. 7F) may also be binned, either physically orvirtually.

In some embodiments of the present invention, LEEs 210 are formed orplaced on base or tape 710, as shown in FIG. 13A. After formation of thephosphor, a frame die structure may include a portion of phosphor 230around and covering all or a portion of the edges of the LEEs 210, asshown in FIG. 13B, which depicts a single frame die, e.g., aftersingulation of the structure depicted in FIG. 13A. In some embodimentsof the present invention, tape or mold substrate 710 is deformable orflexible such that portions of one or more contacts 220 are embeddedinto base or tape 710, for example as shown for LEE 210 in FIG. 13A. Inother embodiments, one or more of the contacts 220 may not be embeddedinto base or tape 710, for example as shown for LEE 210′ in FIG. 13A. Insome embodiments of the present invention, LEE 210 has coplanar orsubstantially coplanar contacts; however, this is not a limitation ofthe present invention, and in other embodiments LEE 210 has non-coplanarcontacts, as depicted by LEE 210″ and LEE 210′″ in FIG. 13A. In someembodiments of the present invention LEE 210 may be tilted, as depictedby LEE 210″ in FIG. 13A, resulting in a frame die structure similar tothat shown in FIG. 13C. The structures shown in FIGS. 13B and 13C showphosphor 230 over a portion of the surface of LEE 210 between contacts220; however, this is not a limitation of the present invention, and inother embodiments this region may only be partially covered withphosphor 230 or may not be covered by phosphor 230.

A frame die structure including a portion of phosphor 230 around andcovering all or a portion of the edges of the LEEs 210 may result inenhanced yield, for example because the die-singulation process, e.g.,when the semiconductor wafer is separated into individual dies, mayresult in chipping or other damage to the passivation at the edge of thedies. If the chipping or damage to the passivation at the edge permitsexposure of underlying conductive semiconductor material, undesirableelectrical coupling to this conductive semiconductor material may occurin the attachment process of a frame die 200, resulting in poor deviceperformance and/or shorting of the device.

In some embodiments of the present invention, one or more portions ofLEE 210 are not covered with phosphor 230, as shown in FIG. 13D. FIG.13D depicts a frame die 200, similar to that shown in FIG. 1A, but witha portion of the sidewall of the body of LEE 210 not covered withphosphor 230. The amount that LEE 210 extends beyond the edge ofphosphor 230 may be identified as the die relief 1350. In someembodiments of the present invention, the die relief 1350 is positive,as shown in FIG. 13D, but in other embodiments die relief 1350 may besubstantially zero, as shown in FIG. 1A, or even negative, as shown inFIG. 13E. In some embodiments of the present invention, die relief 1350may be in the range of about 0 to about 30 μm, or in the range of about0 to about 5 μm.

In various embodiments it may be advantageous that contacts 220 arewithin mechanical and electrical contact range of the conductive tracesto which they will be attached. In some embodiments of the presentinvention, the contacts are not recessed in from the bottom surface ofphosphor 230 and bottom surface of frame 270.

Another dimension of frame die 200 that may be advantageously controlledis a frame-contact relief 1360, as shown in FIG. 13D. The frame-contactrelief 1360 is the amount that the contact protrudes from the adjacentsurface of frame 270 (i.e., the surface of the frame 270 adjacent to,and possibly substantially parallel to, the surface of the LEE 210 onwhich the contact is disposed). In some embodiments, the frame-contactrelief 1360 may be positive, as shown in FIG. 1A and FIG. 13D, while inother embodiments frame-contact relief 1360 may be substantially zero;in other embodiments frame-contact relief 1360 may be negative, as shownin FIG. 13E.

Another dimension of frame die 200 that may be advantageously controlledis frame-phosphor relief 1320, as shown in FIG. 13E. The frame-phosphorrelief 1320 is the amount that frame 270 extends beyond the adjacentsurface of phosphor 230. In some embodiments, the frame-phosphor relief1320 may be positive, as shown in FIG. 13E, while in other embodimentsframe-phosphor relief 1320 may be substantially zero as shown in FIG.1A; in other embodiments frame-phosphor relief 1320 may be negative, asshown in FIG. 13F.

In various embodiments of the present invention, die relief 1350,frame-contact relief 1360, and frame-phosphor relief 1320 may occur indifferent combinations of positive values, substantially zero values,and negative values.

In some embodiments of the present invention, frame die 200 is attachedto conductive traces formed on an underlying substrate using ananisotropic conductive adhesive (ACA); however, this is not a limitationof the present invention, and in other embodiments other techniques andmaterials may be used to attach frame die 200 to underlying traces, forexample solder, solder paste, conductive adhesive, wire bonds, or thelike. In some embodiments of the present invention, the ACA containsconductive particles (e.g., in an insulating matrix) through whichconduction occurs in the z-axis (i.e., between traces and contacts aboveor below such traces). In some embodiments in which the contacts arerecessed from the frame, for example as shown in FIGS. 13E, 13G, and13H, the distance between the outer surface of contact 220 and the lowerpoint of the phosphor or frame, for example the distance between contact220 and the bottom of frame 270 (e.g., corresponding to frame-contactrelief 1360 in FIG. 13E) may be less than the size of the individual ACAconductive particles or less than the minimum size of the individual ACAconductive particles. In some embodiments of the present invention, theACA particles have a size of about 10 μm and the distance between theouter surface of contact 220 and the lower point of the phosphor orframe is less than about 7 μm. In some embodiments of the presentinvention, the ACA particles have a size distribution and the distancebetween the outer surface of contact 220 and the lower point of thephosphor or frame is less than the maximum particle size in thedistribution. In some embodiments of the present invention, the ACAparticles have a size distribution and the distance between the outersurface of contact 220 and the lower point of the phosphor or frame isless than the minimum particle size in the distribution. In someembodiments of the present invention, the distance between the outersurface of contact 220 and the lower point of the phosphor or frame isless than about 75% of the size of the ACA particle, or less than about50% of the size of the ACA particle, or less than about 25% of the sizeof the ACA particle. In such embodiments, if the contacts are notrecessed, for example as shown in FIG. 1A, FIGS. 13B-13D, and FIG. 13F,contacts 220 may be protrude from frame 270 and phosphor 230, as shownin FIG. 1A or protrude from phosphor 230 as shown in FIG. 13F. In someembodiments of the present invention, the thickness of contacts 220 maybe extended by forming additional conductive material over or oncontacts 220 prior to LEE placement step 620 (placement of LEE 210 onmold substrate 710). Such conductive material may be formed by plating,for example electroplating or electroless plating, film deposition(e.g., including evaporation, chemical vapor deposition, physical vapordeposition), bump or stud bump formation, for example through a wirebonding process or the like. In some embodiments of the presentinvention, said conductive material may be formed using solder paste orstencil printing, followed by thermal treatment. For example, FIG. 13Idepicts a conductive material 225 formed over all or a portion ofcontacts 220, extending the effective end of the contact below (orprotruding) from the bottom of frame 270. By modifying the thickness ofmaterial 225, the various dimensional characteristics, such asframe-phosphor relief 1320, frame-contact relief 1360, die relief 1350or the like may be engineered to have specific dimensions. In someembodiments of the present invention, material 225 may be include orconsist essentially of an electrically conductive material, for examplegold, silver, aluminum, tin, copper, solder, or combinations of thesematerials or the like; however, this is not a limitation of the presentinvention, and in other embodiments any electrically conductive materialmay be used.

In some embodiments of the present invention, phosphor 230 absorbs aportion of light emitted by LEE 210 and re-emits it at one or moredifferent wavelengths (i.e., as “converted light”) and the combinationof light emitted by LEE 210 and phosphor 230 (or the “combined light”)defines one or more optical characteristics of frame die 200, forexample color temperature, CRI, R9, spectral power density, or the like.In some embodiments of the present invention, it is advantageous tocontrol the die relief and/or frame-phosphor relief such that multipleframe dies 200 have the same or substantially the same opticalcharacteristics. For example, in some embodiments of the presentinvention, if the die relief is relatively large, then a relativelylarger proportion of light emitted by LEE 210 may be observed directly,without passing through phosphor 230; thus, in some embodiments arelatively small positive die relief is advantageous because it reducesthe amount of light emitted directly from LEE 210 that does not passthrough phosphor 230. In some embodiments of the present invention, thedie relief may be in the range of about 0 to about 30 μm, while in otherembodiments, the die relief may be in the range of about 0 to about 10μm or 0 to about 5 μm. In some embodiments of the present invention, thedie relief is less than about 20% of the height of LEE 210, while inother embodiments the die relief is less than about 10% or less thanabout 5% or less than about 1% of the height of LEE 210. In someembodiments of the present invention, it may be advantageous to reducethe variation in die relief within a composite frame wafer and/orbetween composite frame wafers because it reduces the variation in oneor more optical characteristics of the frame dies. In some embodimentsof the present invention, the variation in die relief is less than about25%, or less than about 10% or less than about 5%, or even less thanabout 1%.

A positive contact relief (the amount the contacts protrude from theframe die bottom surface, including frame 270 and phosphor 230,identified as dimension 1360 in FIG. 13D) may be advantageous from theperspective of making electrical contact to contacts 220. If the contactrelief is negative, it may be difficult to make electrical contact tocontacts 220, for example between contacts 220 and conductive traces orpads on an underlying substrate. In some embodiments of the presentinvention, the contact relief is positive and in the range of about 0 toabout 30 μm. In some embodiments, the contact relief is positive and inthe range of about 1 μm to about 8 μm, or less than about 4 μm. In someembodiments of the present invention, the contact relief is at least theheight of contacts 220; that is, the height that contacts 220 extendabove the surrounding surface of LEE 210. As discussed herein, in someembodiments of the present invention the die relief is negative, but notlarger than the size of ACA particles used to electrically couple thecontact to a conductive trace.

In some embodiments of the present invention, the frame-die relief, theframe-phosphor relief, and/or the die relief may be determined oroptimized and controlled to minimize the amount of light emitted by LEE210 that does not pass through phosphor 230 while providing sufficientcontact and/or die relief to produce a reliable and robust electricalcontact to LEE contacts 220, as well as to produce a reliable and robustmechanical attachment of the frame die 200, for example to an underlyingsubstrate or circuit board.

In some embodiments of the present invention, it is advantageous tocontrol the variation in frame-die relief, the frame-phosphor relief,and/or the die relief on a single composite frame wafer or fromcomposite frame wafer to composite frame wafer. For example, in someembodiments, the variation in frame-die relief, the frame-phosphorrelief, and/or the die relief is less than about 30%, or less than about15%, or less than about 10%. Frame-die relief, frame-phosphor relief,and/or die relief may be controlled by a number of different techniques.In some embodiments, contacts 220 and/or LEEs 210 are partially embeddedin mold substrate 710, as shown in FIG. 13A for LEE 210, and the amountof embedding may be used to control the frame-die relief, theframe-phosphor relief, and/or the die relief.

In one example, frame wafer 720 is formed using anisotropic etching of asilicon wafer, as described in reference to FIGS. 11A-11E. In theexample, an LEE 210 has a length and width of about 180 μm and about 350μm respectively. Gap 242 is about 10 μm, resulting in a bottom and tophole size of about 200 μm and about 370 μm respectively. Three differentsilicon wafer thicknesses were evaluated: 150 μm, 200 μm, and 300 μm.Table 1 shows values and dimensions for each of the three differentwafer thicknesses (configurations 1-3). Table 1 also shows theapproximate number of frames 270 that may be fabricated on a 150 mmdiameter silicon wafer, including an edge exclusion of about 2.5 mm.Table 2 shows results for a larger size square die, having a side lengthof about 1 mm. Increasing the size of the wafer and decreasing thespacing between frame dies may further increase the number of frame dies200 manufactured on one wafer, as shown in configuration 4 of Table 1and 2. As may be seen, a large number of frames 270 may be produced inbatch on each silicon wafer. In some embodiments of the presentinvention, a wafer may include over about 20,000, over 100,000, or over500,000 LEEs 210.

TABLE 1 Configuration 1 2 3 4 Wafer thickness mm 0.150 0.200 0.300 0.150LEE dimension x mm 0.180 0.180 0.180 0.180 LEE dimension y mm 0.3500.350 0.350 0.350 Gap 242 mm 0.010 0.010 0.010 0.005 Bottom hole size -x mm 0.200 0.200 0.200 0.190 Bottom hole size - y mm 0.370 0.370 0.3700.360 Top hole size - x mm 0.412 0.483 0.625 0.402 Top hole size - y mm0.582 0.653 0.795 0.572 Spacing between top holes mm 0.400 0.400 0.4000.100 Wafer diameter mm 150 150 150 300 Edge exclusion on wafer mm 2.52.5 2.5 2.5 Usable wafer area mm 16513 16513 16513 68349 Die + streetarea mm 0.80 0.93 1.22 0.34 # dies per wafer 20689 17751 13485 202319

TABLE 2 Configuration 1 2 3 4 Wafer thickness mm 0.150 0.200 0.300 0.150LEE dimension x mm 1.000 1.000 1.000 1.000 LEE dimension y mm 1.0001.000 1.000 1.000 Gap 242 mm 0.010 0.010 0.010 0.050 Bottom hole size -x mm 1.020 1.020 1.020 1.100 Bottom hole size - y mm 1.020 1.020 1.0201.100 Top hole size - x mm 1.232 1.303 1.445 1.312 Top hole size - y mm1.232 1.303 1.445 1.312 Spacing between top holes mm 0.400 0.400 0.4000.100 Wafer diameter mm 150 150 150 300 Edge exclusion on wafer mm 2.52.5 2.5 2.5 Usable wafer area mm 16513 16513 16513 68349 Die + streetarea mm 2.66 2.90 3.40 1.99 # dies per wafer 6196 5692 4851 34261

Frame wafer 720 having a thickness of about 0.3 mm was fabricated from a(001) silicon wafer using micro-machining techniques described herein.The dimensions of the top and bottom hole were substantially the same asfor Configuration 3 in Table 1. Two reflective coatings were evaluated:(1) about 300 nm of aluminum and (2) about 300 nm of aluminum followedby about 83 nm of SiO₂ and about 60 nm of TiO₂. FIGS. 14A and 14B showthe measured reflectance as a function of wavelength for each of thesecoatings, as deposited on a monitor wafer. From FIG. 14A, thereflectance of the aluminum-only mirror (coating 1) is at least about85% over the visible wavelength range, while the enhanced aluminummirror (with the dielectric films) (FIG. 14B) had a reflectance of atleast about 92% over the visible wavelength range.

These frames were used in the manufacture of frame dies 200 having thestructure shown in FIG. 1E. LEE 210 had substantially the samedimensions as listed in Configuration 3 of Table 1. The overall lengthand width of frame die 200 was about 0.94 mm and about 0.82 mmrespectively. Dimension 245 (FIG. 1E) was about 0.1 mm and about 0.074mm in width and length respectively. The height of the phosphor abovethe top of the frame was about 138 μm. Frame dies 200 were attached toaluminum conductive traces formed on a plastic sheet forcharacterization. The luminous efficacy for the structure with theenhanced aluminum mirror (coating 2 described above) was about 92 lumenper watt at a current drive of 5 mA and a temperature of 50° C. Thetemperature was kept substantially constant by mounting the plasticsheet on a thermoelectric cooler. The optical characterization wasperformed in an integrating sphere.

Advantageously, embodiments of the present invention produce frame dies200 having controlled binder thickness, uniformity and distribution ofphosphor particles in the binder around LEE 210, for example a uniformor substantially uniform thickness and uniform or substantially uniformdistribution of phosphor particles in the binder, or an engineeredthickness and distribution of phosphor particles to achieve uniform orotherwise specified optical characteristics. In some embodiments of thepresent invention, the thickness and/or distribution and/or loading ofthe phosphor particles may have a strong impact on the uniformity of thecolor temperature of the light, for example the variation in CCT fromone frame die 200 to another, either within one frame wafer or betweenframe wafers. In conventional manufacturing approaches, for exampleusing conventional phosphor-integration techniques such as dispensing ofphosphor individually into each package, it may be difficult to achievea desirably uniform phosphor coating over a large number of packages,resulting in non-uniform optical characteristics. In some embodiments ofpresent invention, phosphor coatings over the frame dies may beplanarized after formation, for example to improve phosphor thicknessuniformity and reduce or eliminate optical characteristic variationbetween large numbers of frame dies. Such planarization methods mayinclude or essentially consist of methods such as etching, polishing,grinding, chemical mechanical polishing (CMP) or the like; however thisis not a limitation of the invention, and in some embodiments of thepresent invention thinning may be performed by other techniques.

FIG. 15 is a schematic of the CIE chromaticity diagram with a blackbodylocus 1510 and an ellipse 1520 representing one or more MacAdamellipses. The MacAdam ellipse 1520 has a major axis 1540 and a minoraxis 1530. A MacAdam ellipse represents a region of colors on thechromaticity chart, and a one-step MacAdam ellipse represents the rangeof colors around the center point of the ellipse that areindistinguishable to the average human eye, from the color at the centerof the ellipse. The contour of a one-step MacAdam ellipse thereforerepresents barely noticeable differences of chromaticity.

Multiple-step MacAdam ellipses may be constructed that encompass largerranges of color around the center point. The black body locus is ingeneral aligned with the major axis of a MacAdam ellipse, meaning thatthe eye is less sensitive to color differences along the black body line1510, which equates approximately to red/blue shifts, than todifferences perpendicular to the black body line, which equatesapproximately to a green/magenta shift. Furthermore, with respect tophosphor-converted white light sources, the variation in the minor axisdirection 1530 is in large measure determined by the LEE (e.g., an LED)wavelength variation, while the variation in the major axis direction1540 may be largely determined by the phosphor concentration andthickness. While there are many recommendations as to how tight thecolor temperature uniformity should be (as measured by MacAdam ellipsesor other units), it is clear that a variation encompassed within asmaller step number of MacAdam ellipses (smaller ellipse) is moreuniform than one encompassed within a larger step number of MacAdamellipses (larger ellipse). For example, a four-step MacAdam ellipseencompasses about a 300K color temperature variation along the blackbody locus, centered at 3200K, while a two-step MacAdam ellipseencompasses about a 150K color temperature variation along the blackbody locus, centered at 3200K.

The importance of uniform and/or controlled or engineered thickness andphosphor concentration in frame die 200 may be seen in relation to theMacAdam ellipse on the chromaticity chart of FIG. 15. Since the majoraxis length is largely determined by the phosphor concentration andthickness, variations in these parameters result in an increase in thelength of the major axis of the MacAdam ellipse and thus an increase inthe variation in color temperature. The various methods for fabricationof uniform thickness and composition phosphor as part of frame die 200described herein result in a reduction in the variation in colortemperature and thus a more uniform color temperature light sourcewithin the manufacturing process, resulting in a relatively narrowerdistribution in color temperature. This then permits a reduction incolor temperature variation within a lighting system featuring an arrayof phosphor-converted LEEs, as well as between such lighting systems.The use of the aforementioned LEEs in lighting systems featuring largearrays of LEE permits the manufacture of large numbers of lightingsystems having uniform color temperatures. In some embodiments of thepresent invention, frame dies 200 are manufactured that have adistribution of color temperature less than about 500K, less than about250K, less than about 125K, or less than about 75K. In some embodimentsof the present invention, frame dies 200 are manufactured that have avariation in color temperature or chromaticity of less than about fourMacAdam ellipses, or less than about two MacAdam ellipses, or less thanabout one MacAdam ellipse. In some embodiments of the present invention,such tight distributions are achieved within one composite frame wafer,or within a batch of composite frame wafers or within the entiremanufacturing distribution of frame wafers.

One step in the method of manufacture of some embodiments of the presentinvention is to dispense, cast, pour, apply, or otherwise form aphosphor over one or more LEEs. In one embodiment of the presentinvention, the amount of phosphor formed is controlled by the amount ofphosphor dispensed. In some embodiments, this may be controlled manuallyor under computer or tool control, for example by using a measuredamount or a calibrated syringe or the like, while in other embodimentsthe amount dispensed may be controlled by feedback during the filling ordispensing process. In one embodiment, the amount of phosphor formed iscontrolled by the mold volume. The method of controlling the amount ofphosphor dispensed is not a limitation of the present invention and manytechniques may be used. For example, techniques described in the '864application and in the '543 application may be utilized to control theamount of dispensed phosphor.

The specific values of the geometry of frame die 200 impact the lightoutput power and thus luminous efficacy of frame die 200. As isdiscussed herein, the impact of some dimensional parameters is strongerthan others, some parameters interact with others, and in general theimpact of the geometry of frame die 200 on light output power is reducedas the reflectance of surface 272 (FIG. 1A) (and any other surfaces onwhich light from LEE 210 or phosphor 230 impinge, for example surface276 in FIG. 1E) increases.

FIG. 16A shows the impact of facet angle 279 on total flux, i.e., lightoutput power, for frame dies 200 with different reflectances of surfaces274 and 276. This data is for a structure similar to the one shown inFIG. 1E, with phosphor cap 232 of about 0.1 mm, a frame height 252 ofabout 0.3 mm, a gap 242 of about 5 μm, and a square frame die size 262of about 1 mm, while reflectance of surface 274 and surface 276 varyfrom about 0.25 to about 0.95. The total height of the structure, whichis the sum of the frame height and the height of the phosphor oversurface 276, remains constant in these examples. The extent of surface276 (dimension 245), also known as the flat top, varies as a function ofangle 279. For angle 279 less than about 40°, the flat top dimension issubstantially zero and frame height 252 becomes less than about 0.3 mm.As a result, in these cases, the binder cap height increases above theabout 0.1 mm value to maintain the total frame die height constant atabout 0.4 mm. Data points marked with an “X” on the plot indicateconfigurations in which there is no flat top and the frame height isless than about 0.3 mm.

FIG. 16B shows simulations of the maximum divergence of color uniformityin terms of the radially averaged Δu′v′ deviation from the spatiallyweighted average chromaticity over a view angle of about 0° to about 70°(0° polar angle is looking directly down on the structure shown in FIG.1A) for the structures described in reference to FIG. 16A. In otherwords, the average chromaticity over all polar and azimuthal angles (forexample as measured in an integrating sphere) is first determined, andthen the radially averaged chromaticities at angles between about 0° andabout 70° in units of u′v′ color coordinates are determined, and thenthe maximum difference of the two are plotted in FIG. 16B as a functionof facet angle 279 and reflectance of surfaces 274 and 276. The spatialnon-uniformity of chromaticity (Δu′v′) is measured as the maximumdeviation from the spatially averaged chromaticity as defined in IESLM-79-08, “Electrical and Photometric Measurements of Solid-StateLighting Products,” Illuminating Engineering Society, January 2008(where 0° is perpendicular to the emitting face of LEE 210), the entiredisclosure of which is incorporated by reference herein. The variablesu′ and v′ are chromaticity coordinates on the CIE 1976 chromaticitydiagram.

FIG. 16C shows an exemplary plot of the spatial non-uniformity ofchromaticity (Δu′v′) as a function of polar angle for one azimuthalangle. This data is for a structure similar to the one shown in FIG. 1E,with phosphor cap 232 of about 0.13 mm, a frame height 252 of about 0.3mm, a gap 242 of about 5 μm, and a rectangular frame die size of about0.8 mm by about 0.7 mm, facet angle 54.7, and surface 276 (dimension245), also known as a flat top, of about 0.04 mm. In variousembodiments, for example as shown in FIG. 16C, the divergence of colortemperature of the white light varies, over an angular range of about 0°to about 80°, by no more than about 0.01 in terms of Δu′v′ deviationfrom a spatially weighted averaged chromaticity. In various embodiments,for example as shown in FIG. 16C, the divergence of color temperature ofthe white light varies, over an angular range of about 10° to about 75°,by no more than about 0.005 in terms of Δu′v′ deviation from a spatiallyweighted averaged chromaticity.

As shown in FIGS. 16A and 16B, the total flux increases with decreasingfacet angle 279 and increases with increasing reflectance of surfaces274 and 276. As the reflectance of surfaces 274 and 276 increases, theimpact of facet angle decreases. Thus, frame die structures having areflectance of at least about 85% or at least about 90% on surfaces 274and 276 provide relative more tolerance to varying facet angles thansurfaces having lower reflectance. As shown in FIG. 16B, in generalhigher reflectance of surfaces 274 and 276 results in an improvement inspatial color uniformity and a region of minimum Δu′v′ occurs for facetangle 279 in the range of about 25° to about 55°. In variousembodiments, the maximum Δu′v′ may be less than about 0.01, or less thanabout 0.006, or less than about 0.005, or less than about 0.004.Combining the information from FIGS. 16A and 16B provides a design guideto the impact of structure characteristics on light output power andspatial color uniformity. In applications where high light output poweris most important, the frame dies may have high reflectance surfaces anda low facet angle. In applications where spatial color uniformity ismore important, the frame dies may have high reflectance surfaces and afacet angle in the range of about 25° to about 50°. Using facet angleson the low side of this range, for example in the range of about 30° toabout 40°, will tend to result in higher light output power.

FIGS. 17A and 17B depicts the relationship between facet angle 279 andreflectance of surfaces 274 and 276 on light output power and maximumdivergence of color uniformity in terms of the radially averaged Δu′v′deviation from the spatially weighted average chromaticity over a viewangle of about 0° to about 70° for frame dies 200 similar to the onedepicted in FIG. 1A in which frame die size 262 is not fixed, butinstead varies for different facet angles 279, respectively. In thissimulation, phosphor cap 232 and frame height 252 are constant at about0.1 mm and about 0.3 mm respectively, frame die size 262 ranges fromabout 0.5 mm to about 7.2 mm (frame die size 262 increases withdecreasing facet angle 279), and flat top dimension 245 is essentiallyzero. As shown in FIG. 17A, maximum light output power is achieved whenfacet angle 279 is in the range of about 10° to about 50°, or in therange of about 20° to about 40°. As the reflectance increases, the lightoutput power becomes relatively less dependent on facet angle. As withthe structure described in reference to FIG. 16A, higher reflectancereduces the impact of facet angle 279. FIG. 17B shows that the spatialcolor uniformity improves with increased reflectance and decreased facetangle 279. For facet angles less than about 35°, there is relativelylittle change in spatial color uniformity. In various embodiments, themaximum Δu′v′ may be less than about 0.01, or less than about 0.008, orless than about 0.007, or less than about 0.006. Combining the resultsfrom FIGS. 17A and 17B, a region of facet angles between about 20° toabout 30° achieves high spatial color uniformity and high light outputpower. For reflectances above about 90% or above about 95%, high lightoutput power and high spatial color uniformity is achieved for facetangles less than about 30° or less than about 20° or less than about15°.

FIGS. 18A and 18B depict the impact of facet angle 279 and total framedie height on light output power and maximum divergence of coloruniformity in terms of the radially averaged Δu′v′ deviation from thespatially weighted average chromaticity over a view angle of about 0° toabout 70° respectively, for frame dies having a frame size 262 of 1 mmand aluminum-coated surfaces 274 and 276. For facet angles above about40°, the frame height is fixed at about 300 μm and the total frame dieheight is varied by varying the phosphor cap thickness over the frame.For facet angles below about 40°, the frame height decreases withdecreasing facet angle in addition to the phosphor cap thicknesschanging. Data points marked with an “X” on the plot indicateconfigurations in which there is no flat top and the frame height isless than 0.3 mm.

FIG. 18A indicates that higher light output power is achieved atrelatively low facet angles 279 and for larger phosphor cap thicknesses.Once the total frame die height is greater than about 1 mm, or greaterthan frame size 262, the total light output power is relativelyinsensitive to further increases in the phosphor cap thickness. FIG. 18Bindicates for relatively large facet angles, the best spatial coloruniformity is achieved in thin frame dies, whereas for relatively smallfacet angles the best spatial color uniformity is achieved at frame dieheights in the range of about 0.4 mm to about 1.8 mm, or in the range ofabout 0.4 times to about 1.8 times the frame size 262, or in the rangeof about 0.8 mm to about 1.6 mm or in the range of about 0.8 times toabout 1.6 times the frame size 262. Additionally, there is a change inthe form of the relationship between spatial color uniformity and framedie height for facet angles less than about 20°—below this value thespatial color uniformity is relatively insensitive to frame die height.Combining the information in FIGS. 18A and 18B indicates that relativelyhigh light output power and relatively high spatial color uniformity maybe simultaneously achieved by using relatively low facet angles, forexample below about 25° or below about 15° or below about 5°, and framedie heights above about 0.6 mm. Note that these frame dies do not haveany flat top (indicated by the “X” mark on the curves). In variousembodiments, the maximum Δu′v′ may be less than about 0.01, or less thanabout 0.0075, or less than about 0.005, or less than about 0.0025.

FIGS. 19A and 19B depict the impact of facet angle 279 on light outputpower and maximum divergence of color uniformity in terms of theradially averaged Δu′v′ deviation from the spatially weighted averagechromaticity over a view angle of about 0° to about 70° respectively,for frame dies having a frame die height of about 0.3 mm, essentially noflat top 245, and aluminum coated surfaces 274 and 276. This is similarto the examples shown in FIGS. 16A and 16B, but for two specificphosphor cap thicknesses of about 0.1 mm and about 0.3 mm. As shown inFIGS. 19A and 19B, the thicker phosphor cap (about 0.3 mm) has higherlight output power but also worse spatial color uniformity. As indicatedpreviously, high light output power and good spatial color uniformityare achieved at relatively low facet angles, for example less than about50°, or less than about 40°, and in some embodiments greater than about10°. In various embodiments, the maximum Δu′v′ may be less than about0.01, or less than about 0.006, or less than about 0.004, or less thanabout 0.002.

FIGS. 20A and 20B depict the impact of frame height on light outputpower and maximum divergence of color uniformity in terms of theradially averaged Δu′v′ deviation from the spatially weighted averagechromaticity over a view angle of about 0° to about 70° respectively,for frame dies having a total height of about 0.4 mm, facet angle 279 ofabout 30°, frame die size 262 of about 1.4 mm, and aluminum coatedsurfaces 274 and 276. In these examples, the phosphor cap varies fromabout 0.005 mm to about 0.3 mm, to keep the total height substantiallyconstant at about 0.4 mm. FIGS. 20A and 20B indicate that, in variousembodiments, lower frame height results in relatively higher lightoutput power, but worse spatial color uniformity. In variousembodiments, the maximum Δu′v′ may be less than about 0.01, or less thanabout 0.006, or less than about 0.004, or less than about 0.002.

FIGS. 21A-21D show the impact of frame die scaling on the total lightoutput intensity and maximum divergence of color uniformity in terms ofthe radially averaged Δu′v′ deviation from the spatially weightedaverage chromaticity over a view angle of about 0° to about 70°. Inthese examples, the size of LEE 210 is kept constant, as is the facetangle 279 (30°), and frame height 252, phosphor cap 232, and frame width242 are scaled with the same scaling factor. Increasing the width offrame 244 results in an increase in the total frame die size 262 andalso results in an increase in the frame height because facet angle 279is fixed. Note that frame die size 262 does not scale with the scalefactor, because it is determined by the sum of twice the frame dimension244 and the size of the opening for LEE 210 (265 and 265′ in FIG. 1C).In these examples, the phosphor cap thickness is also scaled with thesame scaling factor. Table 3 summarizes the dimensions for a structurewith no flat top region (data shown in FIGS. 21A and 21B) while Table 4summarizes the dimensions for a structure with a flat top region (datashown in FIGS. 21C and 21D).

TABLE 3 Ratio of Ratio of Frame Frame die Frame Facet Frame die Frameflat top size 262 height Angle Scale Height height die size Phosphordimension to LEE 252 to 279 Factor 252 (mm) 264 (mm) 262 (mm) Cap 232(mm) 245 (mm) size LEE size 30.00 0.60 0.11 0.17 0.74 0.06 0.000 4.10.61 30.00 0.80 0.15 0.23 0.87 0.08 0.000 4.8 0.83 30.00 1.00 0.18 0.281.00 0.10 0.000 5.6 1.00 30.00 1.20 0.22 0.34 1.13 0.12 0.000 6.3 1.2230.00 1.40 0.26 0.40 1.26 0.14 0.000 7.0 1.44 30.00 1.80 0.33 0.51 1.510.18 0.000 8.4 1.83 30.00 2.00 0.37 0.57 1.64 0.20 0.000 9.1 2.06 30.002.40 0.44 0.68 1.90 0.24 0.000 10.6 2.44

TABLE 4 Ratio of Frame Frame die Ratio of Facet Frame die Frame flat topsize 262 Frame Angle Scale Height height die size Phosphor dimension toLEE height 252 279 Factor 252 (mm) 264 (mm) 262 (mm) Cap 232 (mm) 245(mm) size to LEE size 30.00 0.60 0.11 0.17 0.98 0.06 0.24 5.4 0.61 30.000.80 0.15 0.23 1.19 0.08 0.32 6.6 0.83 30.00 1.00 0.18 0.28 1.40 0.100.40 7.8 1.00 30.00 1.20 0.22 0.34 1.61 0.12 0.48 8.9 1.22 30.00 1.400.26 0.40 1.82 0.14 0.56 10.1 1.44 30.00 1.80 0.33 0.51 2.23 0.18 0.7212.4 1.83 30.00 2.00 0.37 0.57 2.44 0.20 0.80 13.6 2.06 30.00 2.40 0.440.68 2.86 0.24 0.96 15.9 2.44

As shown in FIGS. 21A-21D, scaling the frame size while keeping the sizeof the LEE constant has relatively little impact on light output powerand spatial color uniformity, particularly for scale factors largerthan 1. As the scale factor decreases below 1, the frame starts tobecome closer to the size of the LEE, resulting in some degradation inperformance. These results demonstrate that changes in the package size,i.e., the frame size, may be made with little impact on performance, aslong as the package size is not too close to the size of the LEE. Invarious embodiments, the maximum Δu′v′ may be less about 0.006.

In the examples related to Tables 3 and 4 and FIGS. 21A-21D, the LEE hasa length of 350 μm and a width of about 180 μm, and for scale factor 1.0the frame die size 262 is about 1.4 mm. In some embodiments of thepresent invention, the ratio of the size of the frame die to the ratioof the size of the LEE may be used as one factor in the design of aframe die. The last column in Tables 3 and 4 show this ratio, using theshort side of the LEE value, 0.18 mm. In some embodiments, the ratio offrame size to LEE size is greater than about 5 or greater than about 8.In various embodiments, the ratio of frame size to LEE size for framedies without a flat top is greater than about 4 or greater than about4.5 or greater than about 5. In various embodiments, the ratio of framesize to LEE size for frame die with a flat top is greater than the sameratio for frame dies without a flat top. In various embodiments, theratio of frame size to LEE size for frame dies without a flat top isgreater than about 5.5 or greater than about 6.5 or greater than about7.5. As discussed herein, frame die size 262 does not scale directlywith the scale factor—another design ratio shown in Tables 3 and 4 isthe ratio of frame height 252 to LEE size. In various embodiments, theratio of frame height to LEE size for frame dies is greater than about0.5 or greater than about 0.6 or greater than about 1.

FIG. 22 shows plots of light output power for a large number ofdifferent frame die geometries. The variables shown in FIG. 22 includemirror reflectance (of surface 272), frame height 252, total frame dieheight, which is the sum of frame height 252 and binder cap 232, andframe die size (for a square frame). In all cases, LEE 210 has a heightof about 0.14 mm. As shown in FIG. 22 for a perfect mirror(reflectance=1), the geometry of the frame die has relatively verylittle impact on light output power, because in this case substantiallyall of the light is extracted from the package. As the mirrorreflectance decreases, the impact of frame die geometry increases. Insome embodiments, as the frame height decreases, the light output powerincreases. In one embodiment, the light output power generally is morestrongly dependent on geometry when the frame height increases beyondthe height of LEE 210 and generally less dependent on geometry when theframe height is below that of LEE 210. In some embodiments, the lightoutput power increases as the binder cap 232 increases (this may be seenfrom the curves of total frame die height for a fixed frame height). Insome embodiments, the frame die size 262 has less impact on light outputpower than frame height 252 and total frame die height. In someembodiments, as the thickness of LEE 210 becomes substantially the sameas or less than that of frame 252, the light output power becomes lessdependent upon total frame die height. A key aspect of embodiments likethose depicted in FIG. 22 is that, in various embodiments, the mirror(i.e., the reflective frame surface) has as high a reflectance aspossible, reducing the impact of frame die geometry. In someembodiments, the mirror has a reflectance greater than 90%, or greaterthan 95%, or greater than 98%.

The mirrors used in the examples in reference to FIGS. 16A-22 havesubstantially no wavelength dependence and substantially no angle ofincidence dependence; in other words, the reflectance is the same forall angles of incidence and all wavelengths. Aluminum mirrors have verylittle angular or wavelength dependence in the visible wavelength range.However, in some embodiments of the invention, the light incident uponthe mirror and emitted from LEE 210 and/or phosphor 230 is not uniformin wavelength or angle of incidence. In some embodiments of the presentinvention, the mirror or reflecting surfaces may be optimized to matchthe spectral and angular characteristics of the light emitted by LEE 210and/or phosphor 230 to achieve relatively improved opticalcharacteristics.

In some embodiments of the present invention, phosphor 230 absorbs aportion of the light emitted by LEE 210 and re-emits light at adifferent wavelength, the combination of light from LEE 210 and phosphor230 having a different color than that of the light from LEE 210 andphosphor 230 separately. In some embodiments, the combined light issubstantially white light. In some embodiments, the substantially whitelight has a correlated color temperature in the range of about 2500K toabout 10000K. In some embodiments, LEE 210 emits light in the bluewavelength range and phosphor 230 emits light in the green/yellow/redwavelength range.

FIGS. 23A-23C show histograms of the spectral distribution of light froma series of frame dies having three different frame heights 252 (1 μm,150 μm, and 300 μm), emitting substantially white light. In theseexamples, the frame dies have a facet angle 279 of about 54.7°, a gap242 of about 5 μm, and a square frame die size 262 of about 0.98 mm. Asmay be seen from FIG. 23A-23C, the white light is substantially composedof a blue component (dark bars of the histogram) that is emitted fromLEE 210, in the range of about 420 nm to about 490 nm, and a yellowcomponent (light bars of the histogram) emitted from phosphor 230, inthe range of about 500 to about 750 nm. FIGS. 23A-23C also show thedistribution of the angle of incidence on surface 272 as a function ofwavelength. As shown in FIGS. 23B and 23C, for frame thicknesses ofabout 150 μm and about 300 μm, the angle of incidence of the light fromLEE 210 is relatively tightly distributed in the range of about 40° toabout 75°, or about 50° to about 60°, while the angle of incidence ofthe light from the phosphor is more broadly distributed. However, asshown in FIGS. 23B and 23C, most of the light falls within an incidenceangle range from about 30° to about 80° or from about 40° to about 75°.In various embodiments, the peak in the angle of incidence of light fromboth LEE 210 and the phosphor is in the range of about 50° to about 60°,which approximately corresponds to the facet angle produced usingvarious anisotropic etch techniques with a silicon frame.

The dependence of the spectral and angular distribution of light for a 1μm thick frame as shown in FIG. 23A, essentially a flat plate, isrelatively different from those of the structures of FIGS. 23B and 23C.In the case of very thin frames, the spectral distribution is relativelysimilar to that of the other two cases; however, the angle of incidencedependence is shifted to relatively lower angles and is also morebroadly distributed.

FIG. 24A shows a plot of the average value of the blue wavelengths(i.e., light emitted by the LEE) angle of incidence (the angle ofincidence of the peak value of the angle of incidence curve for bluelight) as a function of frame height 252, while FIG. 24B shows a plot ofthe average of the yellow wavelengths (i.e., light emitted by thephosphor) angle of incidence as a function of frame height 252. As maybe seen, in this embodiment, the average value of the angle of incidencefor blue light varies with frame height 252. As frame height 252increases so does the average value of the angle of incidence. Incontrast, in this embodiment, the average value of the angle ofincidence of the yellow light is relatively constant for different frameheights 252.

In some embodiments of the present invention, the information describedin reference to FIGS. 23A, 23B, 24A, and 24B may be used to design anoptimized mirror. For example, for the frame die of FIG. 23C having aframe height 252 of about 300 μm, the mirror may preferably have a peakreflectance for the blue wavelengths at an angle of incidence of about60° and a peak reflectance for the yellow wavelengths at an angle ofincidence of about 50°. For example, for the frame die of FIG. 23Bhaving a frame height 252 of about 150 μm, the mirror may preferablyhave a peak reflectance for the blue wavelengths at an angle ofincidence of about 57° and a peak reflectance for the yellow wavelengthsat an angle of incidence of about 45°. Based on the curves of FIGS. 24Aand 24B, for a frame die having a frame height 252 of about 75 μm, themirror may preferably have a peak reflectance for the blue wavelengthsat an angle of incidence of about 53° and a peak reflectance for theyellow wavelengths at an angle of incidence of about 45°.

The examples described herein are not meant to be limiting and themethodology described in reference to FIGS. 23A-23C and FIGS. 24A and24B may be used to determine the characteristics for an optimized mirrorfor any frame die structure.

In some embodiments of the present invention, circuitry may be disposedin or on frame 270, for example one or more diodes, transistors,resistors, capacitors, inductors, circuits or the like. In variousembodiments, frame 270 may include or consist essentially of asemiconductor material such as silicon, gallium arsenide, or the like,and one or more devices or circuits may be formed in or on thesemiconductor frame 270, for example using conventional semiconductordevice and circuit fabrication techniques. For example, one or moredevices and/or circuits may be fabricated on frame wafer 1110, forexample at a point in time before or after than shown in FIG. 11A. Invarious embodiments, the device(s) and/or circuit(s) may be formed inthe semiconductor frame wafer before fabrication of the frame die. Invarious embodiments of the present invention, one or more circuitelements may be formed on frame 270, for example using hybridsemiconductor packaging techniques such as attachment and electricalcoupling using solder, adhesive, conductive adhesive, ACA, or the like.

In some embodiments of the present invention, a component (which may bea “control element”) 2510 formed in or as part of frame 270 may beelectrically coupled in parallel or series with LEE 210, for example inparallel as shown in FIG. 25A. In various embodiments, component 2510may provide electrostatic protection to LEE 210; for example, in variousembodiments component 2510 may include or consist essentially of a Zenerdiode. In some embodiments, component 2510 may include or consistessentially of one or more electrical devices or circuits. In someembodiments, component 2510 may consist essentially of a Zener diode andLEE 210 may consist essentially of a LED, as shown in FIG. 25B. FIG. 25Cshows a schematic diagram of a frame die having the electrical schematicshown in FIG. 25B, in which component 2510 consists essentially of adiode having Schottky contact 2512 to semiconductor frame 270 and ohmiccontact 2514 to semiconductor frame 270. Schottky contact 2512 iselectrically coupled to contact 220 by conductor 2520 and ohmic contact2514 is electrically coupled to contact 220′ by conductor 2520′. Invarious embodiments, conductors 2520 and 2520′ may be extended to covera relatively large portion of the bottom of the frame die to, e.g.,improve the electrical and/or mechanical attachment of the frame die toa substrate.

In various embodiments, control element 2510 may include or consistessentially of one electrical component, for example a resistor,capacitor, inductor, transistor or the like, or a circuit incorporatingmultiple electrical components. In various embodiments of the presentinvention, component 2510 may include current control and/or voltagecontrol circuitry, for example a current control circuit to control orregulate the current passing through LEE 210. In various embodiments,component 2510 may protect LEE 210 from surge currents. In variousembodiments of the present invention, component 2510 may include arectifying circuit. In various embodiments of present invention,component 2510 may include one or multiple sensing elements such astemperature sensors, vibration sensors, or magnetic sensors, or thelike. In various embodiments of the present invention, component 2510may include light sensors coupled to interior and/or exterior parts offrame 270. In various embodiments of present invention, component 2510may include one or more wireless transmitters and/or receivers. Invarious embodiments of present invention, component 2510 may include anenergy harvesting circuit or material. In various embodiments, component2510 may perform one function, while in other embodiments, component2510 may perform more than one function. For example, in variousembodiments, component 2510 may adjust current through LEE 210 based onoperating temperature that is measured through a temperature sensor ofcomponent 2510. In various embodiment of present invention, component2510 may include identification information for each or a group of framedies, and said information may be utilized to address, actuate, and/orcontrol frame dies individually or in groups. In some embodiments ofpresent invention, component 2510 may permit communication betweenmultiple frame dies and/or with other external components or systems. Invarious embodiments, control element 2510 may be fabricated usingwell-known semiconductor integrated circuit fabrication techniques orhybrid packaging techniques without undue experimentation.

FIG. 26A shows a schematic bottom view of an exemplary frame dieincluding a component 2510 that includes or consists essentially of twoelements 2510′ and 2510″ electrically coupled by conductive elements2610. Component 2510 is electrically coupled to conductors 2520 and2520′, which act as bond pads for the frame die. Contact 220′ of LEE 210is electrically coupled to component 2510″, while the connector betweencomponents 2510′ and 2510″ is also electrically coupled to contact 220.In various embodiments, component 2510′ may be configured to monitorsignals to frame die 210 to permit individual addressing of differentframe dies 210. For example, if a particular frame die is desired to beenergized, component 2510″ may represent a switch that is opened toforce or allow current to flow through LEE 210. If a particular framedie is desired to be off (i.e., not energized), component 2510″ mayrepresent a switch which is closed. Switch 2510″ may have a relativelylow resistance, for example significantly lower than that of LEE 210 andthus shunt current around LEE 210, resulting in LEE 210 not becomingenergized. While component 2510 includes or consists essentially of twoelements in FIG. 26, this is not a limitation of the present invention,and in other embodiments component 2510 may include or consistessentially of fewer or more elements. Conductive elements, for exampleconductive elements 2610, may include one or more conductive films, wirebonds, adhesives, conductive adhesives, ACA, or the like. In variousembodiments, component 2510 may be manufactured and electrically coupledto LEE 210 using well-known semiconductor fabrication techniques and/orhybrid packaging techniques.

FIG. 26B shows another example of a frame die incorporating circuitelements. In various embodiments, component 2510′ may be configured tomonitor the signal to frame die 210 to permit modification of thecurrent to LEE 210. For example, a signal, e.g., a high-frequency signalmodulated onto the power signal to LEE 210, may be demodulated bycomponent 2510′ to determine the desired current for LEE 210, andcomponent 2510″ may include or consist essentially of a current controlcircuit, which provides the desired current to LEE 210. In variousembodiments, either one or both of components 2510′ and 2510″ mayinclude or consist essentially of multiple components, for example oneor more integrated circuit or multiple discrete components.

FIG. 27 shows one embodiment of a lighting system or portion of alighting system 2700 featuring multiple frame dies 200. Lighting system2700 includes an LEE substrate 2720 over which conductive traces 2730have been formed. Frame dies 200 are then formed or placed overconductive traces 2730 such that contacts 220 on LEEs 210 areelectrically coupled with conductive traces 2730. In the example shownin FIG. 27, frame dies 200 are electrically coupled to conductive traces2730 using a connection material 2740, which may include or consistessentially of a conductive adhesive, an anisotropic conductive adhesive(as disclosed in U.S. patent application Ser. No. 13/171,973, filed Jun.29, 2011, the entire disclosure of which is incorporated by referenceherein), a combination of conductive and non-conductive adhesives,conductive epoxy, solder, or the like. In various embodiments, theconnection material 2740 is reflective to a wavelength of light emittedby either or both of LEE 210 and phosphor 230. However, the method ofelectrical coupling and attachment of LEEs 210 or frame dies 200 toconductive traces 2730 is not a limitation of the present invention, andin other embodiments other methods of electrical coupling and attachmentmay be used, for example wire bonding.

In various embodiments the LEE substrate 2720 may include or consistessentially of a semicrystalline or amorphous material, e.g.,polyethylene naphthalate (PEN), polyethylene terephthalate (PET),acrylic, polycarbonate, polyethersulfone, polyester, polyimide,polyethylene, and/or paper. LEE substrate 2720 may also include orconsist essentially of a rigid or flexible circuit board, for exampleFR4, metal core printed circuit board (MCPCB), polyimide or the like.LEE substrate 2720 may be substantially flexible, substantially rigid orsubstantially yielding. In some embodiments, the substrate is “flexible”in the sense of being pliant in response to a force and resilient, i.e.,tending to elastically resume an original configuration upon removal ofthe force. A substrate may be “deformable” in the sense of conformallyyielding to a force, but the deformation may or may not be permanent;that is, the substrate may not be resilient. Flexible materials usedherein may or may not be deformable (i.e., they may elastically respondby, for example, bending without undergoing structural distortion), anddeformable substrates may or may not be flexible (i.e., they may undergopermanent structural distortion in response to a force). The term“yielding” is herein used to connote a material that is flexible ordeformable or both.

In various embodiments, LEE substrate 2720 may include multiple layers,e.g., a deformable layer over a rigid layer, for example, asemicrystalline or amorphous material, e.g., PEN, PET, polycarbonate,polyethersulfone, polyester, polyimide, polyethylene, paint, plasticfilm, and/or paper formed over a rigid or substantially rigid substrate,for example including ceramic such as AlN, fiberglass such as FR-4,metal core printed circuit board, acrylic, aluminum, steel, and thelike. In some embodiments, LEE substrate 2720 is rigid or substantiallyrigid, for example including ceramic such as AlN, fiberglass such asFR-4, metal core printed circuit board, acrylic, aluminum, steel, andthe like.

Depending upon the desired application for which embodiments of theinvention are utilized, LEE substrate 2720 may be substantiallyoptically transparent, translucent, or opaque. For example, LEEsubstrate 2720 may exhibit a transmittance or a reflectivity greaterthan about 80% for optical wavelengths ranging between approximately 400nm and approximately 700 nm. In some embodiments, LEE substrate 2720exhibits a transmittance or a reflectivity of greater than about 80% forone or more wavelengths emitted by LEEs 210 and/or frame dies 200. LEEsubstrate 2720 may also be substantially insulating, and may have anelectrical resistivity greater than approximately 100 ohm-cm, greaterthan approximately 1×10⁶ ohm-cm, or even greater than approximately1×10¹⁰ ohm-cm.

Conductive traces 2730 may include or consist essentially of anyconductive material, for example metals such as gold, silver, aluminum,copper, carbon, and the like, conductive oxides, etc. Conductive traces2730 may be formed on LEE substrate 2720 by a variety of techniques, forexample evaporation, sputtering, physical deposition, chemical vapordeposition, plating, electroplating, printing, lamination, gluing usingan adhesive, lamination and patterning, or the like. In one embodiment,conductive traces 2730 are formed using printing, for example screenprinting, stencil printing, flexo, gravure, ink jet, or the like.Conductive traces 2730 may include or consist essentially of silver,aluminum, copper, gold, carbon inks, or other conductive inks, or thelike. Conductive traces 2730 may include or consist essentially of atransparent conductor, for example, a transparent conductive oxide suchas indium tin oxide (ITO). Conductive traces 2730 may include or consistessentially of a plurality of materials. Conductive traces 2730 mayoptionally feature stud bumps to aid in electrical coupling ofconductive trace 2730 to contacts 220. Conductive traces 2730 may have athickness in the range of about 0.05 μm to about 100 μm; however, thisis not a limitation of the present invention, and in other embodimentsconductive traces 2730 may have any thickness. While the thickness ofone or more of the conductive traces 2730 may vary, the thickness isgenerally substantially uniform along the length of the conductive trace2730 to simplify processing. However, this is not a limitation of thepresent invention and in other embodiments the conductive tracethickness or material varies.

While the discussion above has mainly focused on frame-basedlight-emitting devices that include a phosphor, this approach may beused to economically make light-emitting devices without the phosphor,where the material surrounding the LEE is a transparent material thatdoes not include a light-conversion material, for example replacingphosphor 230 in FIG. 1A with a transparent material, for example abinder or encapsulant. In various embodiments, the transparent materialmay include or consist essentially of epoxy and/or silicone. In variousembodiments of the present invention, other materials may be present inthe binder, for example material to scatter the light. Any or all of thevariations discussed with respect to frame dies includinglight-conversion material may be used or applied to produce frame diesthat do not include a light-conversion material. In some embodiments,LEE 210 may include or consist essentially of an LED. In someembodiments, LEE 210 may emit light in any visible color range, forexample, red, orange, yellow, green, amber, blue, etc., or in wavelengthranges outside of the visible range, e.g., infrared and ultraviolet.

FIG. 28A shows an example of a frame die with a co-molded optical fiber2820. Optical fiber 2820 may be used for, e.g., out-coupling of light ormonitoring of LEE 210 or frame die optical characteristics. Such opticalfiber coupling may be used with frame dies incorporatinglight-conversion materials or with transparent encapsulant materials. Invarious embodiments of the present invention, the optical fiber 2820 maybe attached to the surface of frame die 200, for example using anoptically clear adhesive or glue, or with a polymeric material, forexample similar to the binder in phosphor 230. In various embodiments ofthe present invention, a plurality of optical fibers may be insertedinto uncured or partially cured phosphor 230, and upon curing ofphosphor 230, become physically and optically coupled to frame die 200.

In various embodiments, a clear binder material may be shaped to form anoptic over LEE 210. FIG. 28B shows one example of such a structure, inwhich transparent material 2830 is shaped to form a dome-shaped optic.In various embodiments, material 2830 may have different shapes, forexample to act as a refractive optic, a total internal reflection (TIR)optic, a Fresnel optic, or the like.

In various embodiments, an optical element may be incorporated in aframe die with or without a light-conversion material, for example aspart of the manufacturing process (for example as discussed withreference to FIG. 7R) to produce a structure as shown in FIG. 28C. Theframe die in FIG. 28C includes an optical element 2840 disposed over aphosphor 2850. In various embodiments, phosphor 2850 may or may notinclude one or more light-conversion materials. In various embodiments,the optical element may be aligned with LEE 210 or may be offset, forexample to provide a specific asymmetric light distribution, asdescribed in U.S. patent application Ser. No. 13/693,632, filed on Dec.4, 2012 (the '632 application), the entire disclosure of which isincorporated herein by reference.

In various embodiments an optic may be incorporated after manufacture ofthe frame dies (with or without a light-conversion material), forexample to produce a structure similar to that shown in FIG. 28D. Thestructure of FIG. 28D is similar to that of the structure of FIG. 27,with the addition of an optic 2860. As shown in FIG. 28D, optic 2860includes or consists essentially of one or more optical elements 2865,which in FIG. 28D are each aligned or substantially aligned with a framedie 200.

Optic 2680 typically features an array of optical elements 2685; in someembodiments, one optical element 2685 is associated with each frame die200, while in other embodiments multiple frame dies 200 are associatedwith one optical element 2685, or multiple optical elements 2685 areassociated with a single frame die 200, or no engineered optical elementis associated with any frame die 200, for example optic 2680 may be aplate with a flat or roughened surface. In various embodiments, optic2680 includes elements or features to scatter, diffuse and/or spread outlight generated by frame dies 200. In various embodiments, opticalelement 2865 may be aligned with LEE 210 or may be offset, for exampleto provide a specific asymmetric light distribution, as described in the'632 application.

In various embodiments, optic 2860 may be substantially opticallytransparent or translucent. For example, optic 2860 may exhibit atransmittance greater than 80% for optical wavelengths ranging betweenapproximately 400 nm and approximately 600 nm. In various embodiments,optic 2860 includes or consists essentially of a material that istransparent to a wavelength of light emitted by frame dies 200. Invarious embodiments optic 2860 may be substantially flexible or rigid.In various embodiments, optic 2860 is composed of multiple materialsand/or layers. In various embodiments, optical elements 2865 may beformed in or on optic 2860. Optic 2860 may include or consistessentially of, for example, acrylic, polycarbonate, polyethylenenaphthalate (PEN), polyethylene terephthalate (PET), polycarbonate,polyethersulfone, polyester, polyimide, polyethylene, silicone, glass,or the like. Optical elements 2865 may be formed by etching, polishing,grinding, machining, molding, embossing, extruding, casting, or thelike. The method of formation of optical elements 2865 is not alimitation of embodiments of the present invention.

Optical elements 2865 associated with optic 2860 may all be the same ormay be different from each other. Optical elements 2865 may include orconsist essentially of, e.g., a refractive optic, a diffractive optic, atotal internal reflection (TIR) optic, a Fresnel optic, or the like, orcombinations of different types of optical elements. Optical elements2865 may be shaped or engineered to achieve a specific lightdistribution pattern from the array of light emitters, phosphors andoptical elements.

A space 2870 between the back side of optic 2860 and frame die 200 maybe a partial vacuum or be filled with air, filled with a fluid or othergas, or filled or partially filled with one or more other materials(e.g., solid materials). In various embodiments, space 2870 may befilled or partially filled with a transparent material, similar oridentical to the material that is used as the binder for phosphor 230and/or optical element 2865, to reduce TIR losses in frame dies 200 andto provide enhanced optical coupling between frame dies 200 and optics2865. In some embodiments, space 2870 may be filled with a materialproviding an index of refraction match between frame die 200 and optic2860.

In various embodiments, the optic 2860 may define one or moredepressions 2880 therein, as shown in FIG. 28E, to accommodate orpartially accommodate frame dies 200. Frame dies 200 may be formed orinserted into depressions 2880, for example in a batch process or usinga pick-and-place tool. Frame dies 200 may be held in depressions 2860mechanically, or with an adhesive or glue. In various embodiments, framedies 200 may be held in place by a transparent material similar oridentical to the binder or matrix used in phosphor 230. In variousembodiments, depression 2880 may be larger than frame die 200. Invarious embodiments, depression 2880 is sized to just accommodate framedie 200 such that frame die 200 fits snugly within the depression 2880.FIG. 28F shows an example of an embodiment of the present inventionincorporating an optic 2860 having depression 2880 with a frame dietherein. In various embodiments, optic 2860 may be incorporated beforeor after the frame die is electrically coupled to conductive traces2730. As discussed with respect to FIG. 28D, space 2870 may be a partialvacuum or be filled with air, filled with a fluid or other gas, orfilled or partially filled with one or more other materials.

While the discussion above has mainly focused on light-emitting devices,embodiments of the present invention may also be used for devices thatabsorb light, for example detectors or photovoltaic devices, asdescribed in the '864 application and the '543 application. FIG. 29Ashows an exemplary device (or “frame die”) 2900 that includes alight-absorbing element (LAE) 2910 and binder 2920 with a frame 270. Inone embodiment, LAE 2910 is configured with a flip-chip geometry, inwhich contacts 220 are positioned on a face opposite a detecting face2930. In various embodiments, the substrate (e.g., the semiconductorsubstrate) for LAE 2910 is partially or completely removed. LAE 2910 maybe configured to detect one or more wavelengths over a wide range ofwavelength ranges, both within and/or outside the visible lightspectrum. In various embodiments, LAE 2910 may be configured to detectUV light, IR light, x-rays, visible light, or any portion of theelectromagnetic spectrum for which a detector is available. In someembodiments, LAE 2910 may include GaAs, InAs, AlAs, GaN, InN, AlN, GaP,InP, AlP, InGaP, InAlP, InGaAlP, ZnO, II-VI materials or the like, orvarious combinations of two or more of these materials. The materialfrom which LAE 2910 is composed is not a limitation of the presentinvention.

In some embodiments LAE 2910 may be a Schottky detector, a p-n junctiondetector, a photoelectric detector, a photocell, a photoresistor, aphotodiode, a phototransistor, a charge-coupled device, a CMOS imager,or the like. The type of LAE 2910 and method by which LAE 2910 operatesare not limitations of the present invention.

In various embodiments, binder 2920 is transparent to a wavelength oflight to be detected by LAE 2910. In one embodiment, binder 2920 may bepartially absorbing and the absorption band of binder 2920 may be usedto select one or more wavelength ranges to be detected by LAE 2910 fromthe range of incident wavelength ranges. For example, binder 2920 mayeffectively act as a low-pass filter, a high-pass filter, a bandpassfilter, or various combinations of these.

In some embodiments, binder 2920 may further include other materials toenhance one or more aspects of the performance of device 2900. Forexample, in one embodiment, binder 2920 may include materials to absorbone or more wavelengths of light, to act as a filter. In one embodimentbinder 2920 includes a wavelength-conversion material, similar tobinders and wavelength-conversion materials described above. In oneembodiment, this may be used to shift an incident wavelength to adifferent wavelength to be detected by LAE 2910. For example awavelength-conversion material may be added to binder 2920 to shift oneor more wavelengths of incident light (e.g., blue light) to one or moredifferent wavelengths (e.g., yellow light) that impinge on LAE 2910. Inthis way, one or a small number of LAEs 2910 may be used in combinationwith a number of wavelength-conversion materials to produce a family ofdetectors spanning a wide wavelength range, without the need to have arelatively large number of different LAEs 2910.

As discussed herein with respect to frame dies incorporating LEEs,binder 2920 may be shaped. In some embodiments, binder 2920 is shaped toincrease the collection of light by LAE 2910. FIG. 29B shows anexemplary device 2901 having shaped binder 2920 that has a dome-likeshape. In various embodiments, shaped binder 2920 is combined with oneor more additives, for example a wavelength-conversion material.

In some embodiments, a device may include more than one LAE 2910. Invarious embodiments, a device 2902 includes three LAEs 2910, identifiedas LAEs 2910, 2910′, and 2910″ in FIG. 29C. In various embodiments, LAE2910 detects red wavelengths, LAE 2910′ detects green wavelengths, andLAE 2910″ detects blue wavelengths, and the combination may be used as acolor sensor by evaluating the relative output signals from the threedifferent LAEs.

In some embodiments, LAE 2910 is a photovoltaic device or solar cell,and is designed to produce power from incident radiation (typically, butnot necessarily, in the visible range). Such a photovoltaic device maybe made of a wide variety of materials. In some embodiments, LAE 2910may include GaAs, InAs, AlAs, GaN, InN, AlN, GaP, InP, AlP, InGaP,InAlP, InGaAlP, ZnO, II-VI materials or the like or various combinationsof two or more of these materials. The material from which LAE 2910 ismade is not a limitation of the present invention. In some embodiments,LAE 2910 is a single-junction solar cell, while in other embodiments LAE2910 is a multi-junction solar cell. As discussed herein with respect tolight-emitting elements and detectors, photovoltaic devices producedusing embodiments of the present invention may include in variousembodiments a transparent binder, additives to the binder,wavelength-conversion materials, shaped binder, optics, multiple LAEs2910 per device, and the like.

In some embodiments, a photovoltaic device made in accordance withembodiments of the invention may additionally include one or more opticsto increase collection or to act as concentrators, similar to thatdescribed herein with respect to light-emitting devices. In variousembodiments, the optical function for collection or concentration iscarried out using a shaped binder 2920.

In some embodiments, binder 2920 may further include other materials toenhance one or more aspects of the performance of devices 2900-2092. Forexample, in one embodiment, binder 2920 may include materials to absorbone or more wavelengths of light, to act as a filter. In one embodiment,binder 2920 includes a wavelength-conversion material, similar to thatdescribed above with respect to devices incorporating light-emittingelements. In one embodiment, this may be used to shift an incidentwavelength to a different wavelength to be absorbed by LAE 2910. Forexample, a phosphor may be added to binder 2920 to shift one or morewavelengths of incident light to one or more different wavelengths oflight that impinge on LAE 2910. In this way a larger portion of thesolar spectrum may be usefully absorbed by LAE 2910. In someembodiments, this may permit the use of a lower cost LAE 2910, forexample one with fewer junctions. In one embodiment, more than onedifferent LAE 2910, each absorbing light in a different wavelengthrange, may be incorporated into one packaged device.

Embodiments of the present invention may be applied to devices thatneither emit nor detect light, identified as electronic-only devices,where the purpose of application of this invention is, in someembodiments, reduction in cost. In various embodiments, a relativelylarge number of electronic devices, specifically chips or discretedevices or integrated circuits may be packaged in a polymer-basedmaterial (like the binder detailed above) using a high-volume, low-cost,base process. In some embodiments of this approach, binder 2920 need notbe transparent but may be translucent or opaque. As discussed hereinwith respect to light-emitting elements, detectors, and photovoltaicdevices, electronic-only devices produced in accordance with embodimentsof the present invention may include additives to the binder, shapedbinder, multiple devices, and the like.

In various embodiments, an electronic-only device of the presentinvention is a packaged electronic-only device. In some embodiments,electronic-only devices may have a larger number of contacts than woulda light emitter or a detector. For example, an electronic-only devicemay include more than ten contacts or more than 100 contacts or an evenlarger number of contacts.

In various embodiments of the present invention, additional elements maybe incorporated, for example a heat spreader, heat pipe or a connector,or multiple dies may be stacked on top of each other, as described inthe '864 application and the '543 application.

In various embodiments, electronic-only and other (for examplelight-absorbing and/or light-emitting) devices may be packaged in thesame binder, as shown in FIG. 29D. FIG. 29D shows electronic-only device2940 adjacent to light-detection device 2910. This approach may be usedto provide some additional capability, for example signal conditioning,communications, memory, or the like. In one embodiment, electronic-onlydevice 2940 and light-detection device 2910 communicate through each oftheir respective contacts by way of connections on the circuit board towhich they are ultimately mounted. In various embodiments, internalconnections may be used, for example vias, wirebonds, wirelesscommunication links, or the like.

In various embodiments of the present invention, frame 270 and/or framewafer 720 may include or consist essentially of a material transparentto a wavelength of light emitted by LEE 210 and/or phosphor 230, forexample glass, quartz, sapphire, aluminum oxide, aluminum oxinitride(AlON), silicon carbide, other transparent oxides, or polymers, forexample silicone or epoxy. In various embodiments of the presentinvention, frame 270 and/or frame wafer 720 may include or consistessentially of low-temperature glass, an example of such material isHitachi chemical's low-melting vanadate glass series. In variousembodiments of the present invention, glass frame 270 may bemanufactured using one or more of the following techniques; wet chemicaletching, dry etching, reactive ion etching, molding, casting, ablation,bonding, machining, rapid prototyping, three-dimensional printing,ultrasonic machining, abrasive machining, or the like.

FIG. 30A shows an exemplary device of the present invention thatfeatures a glass frame 3010. In various embodiments, glass frame 3010may be transparent to a wavelength of light emitted by LEE 210 and/orphosphor 230. In various embodiments, glass frame 3010 may have atransmittance to a wavelength of light emitted by LEE 210 and/orphosphor 230 greater than about 75%, greater than about 85%, greaterthan about 90%, or greater than about 95%. In various embodiments, allor portions of surfaces 240 and/or 250 may be reflective to a wavelengthof light emitted by LEE 210 and/or phosphor 230. In various embodiments,all or portions of surfaces 240 and/or 250 may have a reflectance to awavelength of light emitted by LEE 210 and/or phosphor 230 greater thanabout 75%, greater than about 85%, greater than about 90%, or greaterthan about 95%. In various embodiments, all or portions of surfaces 240and/or 250 may be coated with a material having a reflectance greaterthan about 75%, greater than about 85%, greater than about 90%, orgreater than about 95% to a wavelength of light emitted by LEE 210and/or phosphor 230. FIG. 30B shows an exemplary device of the presentinvention featuring a glass frame 3010 and a reflective layer 3020covering substantially all of the bottom of glass frame 3010.

In various embodiments of the present invention, reflective layer 3020may include or consist essentially of one or more metal layers, forexample aluminum, silver, gold, chromium, titanium, or the like. Invarious embodiments of the present invention, reflective layer 3020 mayinclude or consist essentially of one or more layers, for exampleincluding one or more dielectric and/or metallic layers. The specificlayer structure of reflective layer 3020 is not a limitation of thepresent invention. In various embodiments of the present invention, thelayers of reflective layer 3020 may include or consist essentially of aBragg reflector. In various embodiments of the present invention, thereflecting surface may be a specular or diffuse reflecting surface. Invarious embodiments of the present invention, layer 3020 may include orbe covered by a dielectric material such as silicon oxide, siliconnitride, titanium oxide, aluminum oxide, or a polymer. Said insulatinglayer may minimize or prevent the flow of electrical current fromunderlying conductive traces through layer 3020, resulting in areduction or elimination in current flowing to LEE 210. While thediscussion related to reflecting layer 3020 is directed to reflectinglayer 3020 formed on all or a portion of surface 240, this is not alimitation of the present invention, and in other embodiments areflecting layer may be formed on all or a portion of other surfaces,for example surface 250, surface 272 or a portion of the surface ofphosphor 230.

In various embodiments of the present invention, the index of refractionof transparent frame 3010 may be the same or substantially the same asthe index of refraction of the binder material in phosphor 230. Invarious embodiments, such index matching leads to substantialtransmission of light emitted by LEE 210 and/or by phosphor 230 throughtransparent frame 3010, resulting in a structure having similarcharacteristics to a non-transparent frame with a very low(substantially zero) facet angle 279. As shown in FIG. 30B, light 3030from LEE 210 may be transmitted through transparent frame 3010, inessence creating a frame die structure with a facet angle 279 close tozero (for example similar to that of FIG. 1M or FIG. 1N). In variousembodiments, as discussed herein, very low facet angle 279 may result inimproved angular spatial color uniformity. In various embodiments, verylow facet angle 279 may result in higher light output power. In variousembodiments, it may be relatively more straightforward to manufacture ahigh reflectance coating on surface 240, which is flat, than on surface272, which is angled.

As discussed with respect to the structures of FIGS. 1A-1AA, the shapeof a transparent frame may be engineered to achieve specificcharacteristics, for example high light output power and good angularspatial color uniformity. For example, in various embodiments in whichthe index of refraction of transparent frame is matched or substantiallymatched to that of phosphor 230, the specific shape of the frame is lesscritical and thus may be engineered for lower cost and/or easiermanufacture. FIG. 31A shows an exemplary embodiment in which frame 3010is essentially a rectangular solid with a through-hole for LEE 210.

In various embodiments, phosphor may be formed on all or portions of theoutside of transparent frame 3010, for example as shown in FIGS. 31B and31C. In various embodiments of the structure shown in FIG. 31B, formingphosphor 230 on the outside of frame 3010 permits formation of astructure having phosphor 230 surrounding LEE 210, such that all orsubstantially all of the light emitted by LEE 210 is absorbed byphosphor 230 or exits the structure, without reflection from anothersurface, for example surface 272 of a non-transparent frame die. Thestructures of FIGS. 31B and 31C are enabled by, for example, thesingulation of the frame wafer and then coating of phosphor over the cutedges. The structures of FIGS. 31D and 31E present exemplary structuresto avoid a post-frame-wafer singulation step. These and similarstructures incorporate recesses 3110 in the outer portion of the framethat are filled with phosphor 230 and/or grooves 3120 that are filled orpartially filled with phosphor 230, both of which lead to more completesurrounding of LEE 210 by phosphor 230. FIGS. 31F and 31G show planviews of two exemplary structures in which the frame incorporates holes3130 which penetrate completely through frame 3010, permitting formationof phosphor 230 down to the bottom of the structure, as compared to thestructure of FIG. 31E in which phosphor 230 does not extend to thebottom of the structure, while maintaining a one-piece frame. The twoembodiments shown in FIGS. 31F and 31G have different shapes andlocations for grooves 3130. The shape and location of grooves 3130 ortrenches 3120 are not limitations of the present invention.

In various embodiments, a transparent frame may be shaped to engineerspecific optical characteristics, for example to control or engineer aspecific spatial intensity or spatial color distribution. In variousembodiments of the present invention, the shaped surfaces may bereflective, or coated with a reflective coating or may form all orportion of a total internal reflection (TIR) surface. A TIR surface isan interface between two materials having different indices ofrefraction, such that light is reflected at the interface, rather thanbeing transmitted, when the light is incident at an angle greater than acritical angle determined mainly be the different indices of refractionof the two materials (for example, as may be determined by Snell's Law).FIG. 31H shows an exemplary embodiment of a structure including a TIRsurface. TIR surface 3140 represents the boundary between frame 3010 andthe surrounding medium, for example air. In various embodiments, theindex of refraction of the surrounding medium is less than that of frame3010, resulting in a critical angle above which light incident uponsurface 3140 will be reflected (reflected internally in frame 3010).According to Snell's law, the critical angle is given byθ_(C)=arcsin(n₂/n₁) where n2 and n1 are the indices of refraction of thesurrounding medium and of the frame material respectively. For example,frame material 3010 may have an index of refraction of about 1.5,resulting in a critical angle of about 41.8° (for the surrounding areabeing air with an index of refraction of about 1.0). In variousembodiments, the shape (e.g., curvature) of surface 3140 is engineeredto totally internally reflect light emitted from LEE 210 over aparticular or substantial range of emission angles (and thus anglesincident upon surface 3140). In various embodiments, frame 3010 andphosphor 230 have the same or substantially the same index ofrefraction, and thus the direction of light incident upon the boundarybetween frame 3010 and phosphor 230 is substantially unchanged (i.e.,there is little if any reflection or refraction of light at the boundarybetween frame 3010 and phosphor 230). In various embodiments, surface240 may be reflective or coated with a coating reflective to awavelength of light emitted by LEE 210 and/or phosphor 230. In variousembodiments, light from 210 and/or phosphor 230 is transmitted throughtransparent frame die 3010 and reflected off of TIR surface 3140 andoptionally reflective surface 240. By shaping the TIR surface, thespatial intensity distribution of the structure may be engineered tohave a specific distribution. Additionally, the inner sidewalls 3150and/or top surface 3160 of frame 3010 may be reflective or partiallyreflective or may be coated with a material having a reflectance to awavelength of light emitted by LEE 210 and/or phosphor 230.

In various embodiments of the present invention, a reflective coatingmay be formed on all or portions of one or more faces of the transparentframe, for example faces 230, 276, 274, and 240 as shown in FIG. 31I. Invarious embodiments, as discussed herein, the characteristics, forexample spectral regions of relatively high reflectance or angularregions of incidence, of the reflective coatings may be optimized toachieve specific frame die optical characteristics, for example lightoutput power and spatial color uniformity.

In various embodiments of the present invention, various portions of atransparent frame may have different optical characteristics, forexample to engineer a specific spatial color or intensity distributionor to improve the spatial color uniformity. For example, in variousembodiments, various portions of a transparent frame may absorb orpartially absorb one or more portions of the spectrum of light emittedby LEE 210 and/or phosphor 230. In various embodiments, various portionsof a transparent frame may include scattering features, for example toscatter light emitted by LEE 210 and/or phosphor 230, for exampleisotropically or in one or more particular directions. In variousembodiments, scattering features may include particles within thetransparent frame, voids within the transparent frame, modifications tothe surface of the transparent frame, for example indentations,protrusions or other surface features, or features formed or printed onthe surface of the transparent frame.

As discussed herein, in some embodiments all or a portion of the surfaceof phosphor 230 may be roughened or textured, for example to reduce TIRand increase the light output or to increase adhesion between phosphor230 and an adjacent material, for example to increase adhesion to anadjacent optic. In some embodiments, roughening or texturing may takeplace during the molding process. In some embodiments, all or a portionof the mold substrate surface in contact with the uncured phosphor maybe roughened or textured to impart such roughened or textured featuresto cured phosphor 230. In some embodiments, such roughening or texturingmay be accomplished after molding, for example by ablation, laserablation, etching or chemical ablation, imprinting, indenting or thelike. The method of roughening or texturing is not a limitation of thepresent invention.

In one embodiment, the textured features may have a size in the range ofabout 0.1 μm to about 50 μm and more preferably in the range of about0.5 μm to about 25 μm. In one embodiment, the texture may behemispherical or pyramidal in shape; however, this is not a limitationof the present invention, and in other embodiments the texture may haveany shape. In one embodiment, the texture includes or consistsessentially of a regular or substantially regular pattern, while inother embodiments the texture includes or consists essentially of randomor substantially random features. In some embodiments, the scale of thetexture is advantageously less than about 10% of the height of LEE 210,or less than 5% of the height of LEE 210 or less than 2% of the heightof LEE 210, in order to reduce occlusion or absorption of light emittedby LEE 210.

In various embodiments frame dies may include a portion of the phosphorhaving a texture, or a portion of the phosphor covered or overlaid witha reflecting layer, or both. In some embodiments, the reflecting layeritself may be textured, while in other embodiments the texture isseparate from the reflecting layer.

While the discussion herein mainly focuses on down-conversion, that isthe use of a wavelength-conversion material or phosphor to shift a shortwavelength to a longer wavelength, that is not a limitation of thepresent invention and in other embodiments up-conversion or acombination of up-conversion and down-conversion may be used.

Other embodiments of this invention may have additional or fewer stepsor components or may be modified or carried out in a different order. Ingeneral in the above discussion the arrays of light emitters, wells,optics and the like have been shown as square or rectangular arrays;however, this is not a limitation of the present invention and in otherembodiments these elements are formed in other types of arrays, forexample hexagonal, triangular or any arbitrary array. In someembodiments, these elements are grouped into different types of arrayson a single substrate.

The terms and expressions employed herein are used as terms andexpressions of description and not of limitation, and there is nointention, in the use of such terms and expressions, of excluding anyequivalents of the features shown and described or portions thereof. Inaddition, having described certain embodiments of the invention, it willbe apparent to those of ordinary skill in the art that other embodimentsincorporating the concepts disclosed herein may be used withoutdeparting from the spirit and scope of the invention. Accordingly, thedescribed embodiments are to be considered in all respects as onlyillustrative and not restrictive.

What is claimed is:
 1. A method of forming a composite frame wafercomprising (i) a frame wafer defining a plurality of aperturestherethrough and (ii) a plurality of discrete semiconductor diessuspended in a cured polymeric binder within the apertures, the methodcomprising: providing a frame wafer (i) having a bottom surface, (ii)having a top surface opposite the bottom surface, (iii) having athickness spanning the top and bottom surfaces, and (iv) defining aplurality of apertures (a) each extending fully through the thicknessand (b) each having a sidewall, the top surface of the frame wafersurrounding each aperture; disposing the frame wafer over a moldsubstrate; disposing the plurality of discrete semiconductor dies on themold substrate within the apertures, each semiconductor die having atleast two spaced-apart contacts adjacent the mold substrate; coating atleast a portion of the frame wafer and the plurality of semiconductordies with a polymeric binder; curing the polymeric binder to form thecomposite frame wafer; and separating the composite frame wafer from themold substrate, wherein the contacts of each semiconductor die remain atleast partially uncoated by the polymeric binder.
 2. The method of claim1, wherein (i) one or more of the semiconductor dies is a bare-dielight-emitting element and (ii) the polymeric binder is transparent to awavelength of light emitted by the one or more semiconductor dies. 3.The method of claim 1, further comprising separating the composite framewafer into a plurality of discrete portions, each portion comprising (i)a portion of the frame wafer defining an aperture therethrough and (ii)disposed within the aperture, at least one semiconductor die coated withcured polymeric binder.
 4. The method of claim 1, further comprising:disposing a second substrate in contact with the composite frame waferbefore the composite frame wafer is separated from the mold substrate,wherein the composite frame wafer remains attached to the secondsubstrate when the composite frame wafer is separated from the moldsubstrate.
 5. The method of claim 1, wherein, after separation of thecomposite frame wafer from the mold substrate, a portion of a bottomsurface of the composite frame wafer is defined by exposed surfaces ofthe semiconductor dies proximate the contacts thereof.
 6. The method ofclaim 2, wherein the frame wafer is transparent to a wavelength of lightemitted by the light-emitting element.
 7. The method of claim 2, whereinat least a portion of the sidewall of at least one of the apertures isreflective to a wavelength of light emitted by the light-emittingelement.
 8. The method of claim 2, wherein the polymeric binder containsa wavelength-conversion material for absorption of at least a portion oflight emitted from the semiconductor dies and emission of convertedlight having a different wavelength, converted light and unconvertedlight emitted by the semiconductor dies combining to form mixed light.9. The method of claim 3, wherein after separation, a volume ofpolymeric binder surrounding each semiconductor die is substantiallyequal.
 10. The method of claim 4, further comprising separating thecomposite frame wafer from the second substrate.
 11. The method of claim6, further comprising forming a reflective layer on at least a portionof the frame wafer.
 12. The method of claim 7, wherein the at least aportion of the sidewall has a reflectance greater than 80% to awavelength of light emitted by the light-emitting element.
 13. Themethod of claim 7, wherein the at least a portion of the sidewall iscoated with a reflective coating that is reflective to a wavelength oflight emitted by the light-emitting element.
 14. The method of claim 8,wherein at least a portion of the sidewall of at least one of theapertures is coated with reflective coating having a reflectance greaterthan 80% to a wavelength of light emitted by the light-emitting elementand/or the wavelength-conversion material.
 15. The method of claim 8,wherein the polymeric binder comprises a plurality of discrete regions,at least one of which comprises the polymeric binder without thewavelength-conversion material.
 16. The method of claim 8, wherein themixed light comprises substantially white light.
 17. The method of claim16, wherein the substantially white light has a correlated colortemperature in the range of 2000 K to 10,000 K.
 18. The method of claim16, wherein a variation in the color temperature of the substantiallywhite light emitted when each semiconductor die is individuallyenergized is less than four MacAdam ellipses across the composite framewafer.
 19. The method of claim 16, wherein a variation in the colortemperature of the substantially white light emitted when eachsemiconductor die is individually energized is less than 500 K acrossthe composite frame wafer.
 20. The method of claim 16, wherein a maximumdivergence of color uniformity in terms of the radially averaged Δu′v′deviation from the spatially weighted average when each semiconductordie is individually energized is less than 0.01 across the compositeframe wafer.
 21. The method of claim 16, wherein a divergence of colortemperature of the substantially white light emitted when eachsemiconductor die is individually energized, varies, over an angularrange of 0° to 80°, no more than 0.006 in terms of Δu′v′ deviation froma spatially weighted averaged chromaticity across the composite framewafer.